AUTOMOTIVE OPERATION
AND MAINTENANCE
By E. Christopher Cone
A manual for drivers using pioneer roads and for novice
mechanics who must depend upon their own resources
in areas without extensive service facilities.
Volunteers in Technical Assistance
1600 Wilson Bloulevard, Suite 500
Arlington, Virginia 22209-8438 USA
Automobile Operation and Maintenance
Copyright [C] E. Christopher Cone, 1992
All rights reserved. No part of this publication may be reproduced or transmitted in
any form or by any means, electronic or mechnical, including photocopy, recording,
or any information storage and retrieval system without written permission of the
publisher.
Published by Volunteers in Technical Assistance (VITA)
1600 Wilson Bloulevard, Suite 500
Arlington, Virginia 22209-8438 USA
Manufactured in the United States of America.
Library of Congress Cataloging-in-Publication Data
Cone, E. Christopher.
Automotive operation and maintenance/ by E. Christopher Cone. [Revised
Edition] Includes index.
ISBN 0-86619-310-3
1. Automobiles--Maintenance and repair. 2. Automobile driving.
I. Title.
TL 152.C58 1992 926.28'72-dc20 90-49886 CIP
First printing, May 1973
Second printing, November 1973
Third printing, April 1974
Revisions and fourth printing, April 1975
Revisions and fifth printing, July 1992
DEDICATION
This book is dedicated to the memory of Fr. Joseph Bessom, OHC, a
modern-day Christian saint whose love of Africa and its people sent me to
live in its jungles and resulted in the writing of this book for VITA.
ACKNOWLEDGEMENTS
It would be fruitless to attempt to list all of the men and women who have
contributed to the preparation of this book. They range from unlettered Africans
with an inborn feeling for the capacity of a log bridge to engineers with the some
of the largest corporations in the world. Special thanks should be made to my
African instructors, James Tamba Kila, Stephen Boakai, Jaka Masambolahun,
James Nyuma Dah, Moses Sivili Gelego, Andrew Kpehe Woiwor, and others.
Appreciation is extended to the Order of the Holy Cross, which provided the
"test track" for most of the material discussed in this book. Acknowledgement
is also made of the assistance of several people at VITA, notably Terry Ladd and
Gerri Forlenza, who worked on the first edition, and Patricia Mantey and
Margaret Crouch, who prepared the current, revised version.
Special thanks go to VITA Volunteer John N. Amon of the Rochester Institute
of Technology, who produced all new technical drawings for the fifth printing
using Intergraphic MicroStation software, and Celia Jenkins and Jill Smith
McClain, who assisted with the photographs.
The technical assistance of many vehicle manufacturers and their sales agents
has contributed to the production of this book. Their aid has been invaluable in
providing shop references concerning specific vehicles in the maintenance
portion of this manual.
E.C.C.
INTRODUCTION
This book is intended to fill a need found by the author at the start of his 30 years
as a mechanic for a church mission in Liberia, West Africa. At that time the
author could perhaps charitably be termed a mechanically inclined novice.
Despite his lack of experience he found himself in charge of a substantial
number of vehicles and a fair-sized electric generating station. It was largely
through experiment and occasional disaster that much of the material for this
book was assembled. It is presented here in the hope that it may save the reader
from many of the same problems.
The intent is to offer suggestions to drivers or mechanics who operate in an area
where service facilities and technical assistance are not readily available and
they must be their own advisers on every problem that may arise. In the event
that readers happen to have some service facilities at hand, they will find that
they can skip over some sections of the manual.
This manual for the most part deals with four-wheel drive vehicles, since it can
generally be expected that an area where no service facilities exist will be one
with pioneer roads, which require the added traction of four-wheel drive.
However, since FWD is the name of a manufacturer of heavy-duty, four-wheel
drive trucks, it is inappropriate to use this abbreviation to indicate "four-wheel
drive." The abbreviation FWD is also used to describe the growing number of
cars with front-wheel drive and no power in the rear wheels. To avoid confusion,
the term 4WD will be used here. Also, as a matter of convenience, the word "car"
is taken as it is used in West Africa: to mean any sort of small or moderate size
vehicle whether it be a sedan automobile, Jeep-type vehicle, or pickup truck.
On another matter of nomenclature, it should be noted that petroleum products
are identified here by their U.S. names. Readers in other areas will have to
translate according to local custom. This is a matter of some confusion; what the
British call paraffin, for example, is known as kerosene in the United States, and
paraffin to a U.S. reader means a translucent white wax.
The book is organized into several sections. An understanding of the organization
should make it possible to find needed material quickly. The first section
concerns operation of a car in an area served by pioneer roads. This section is
intended to assist drivers with temporary repairs to the vehicle so that they can
get home in the event of mechanical trouble.
The second section of the book is devoted to maintenance suggestions, which
are intended for use in a frontier shop or repair center, no matter how ill-equipped
it may be. This book should be used as a supplement to the vehicle's
shop manual. For example, this book will help indicate when brakes need to be
relined, but the shop manual will tell how to do it. Since a book of this type is
worthless if material cannot be located when it is needed, a special effort has
been made to prepare as complete an index as possible. Cross references will
also be found throughout the text.
NOTE regarding metric and English measurements: For convenience both
systems of measurement are used in this book. Where an equivalent is given as
a "rule of thumb," however, it is not intended as an exact equivalent. For
example, 35 miles per hour is shown as being equivalent to 55 kilometers per
hour. A more exact figure would be 56.35 kilometers per hour, but this is
cumbersome and not readily remembered.
A complete table of English and metric equivalents is included in Section 20.00.
TABLE OF CONTENTS
Major sections of this book are divided by section numbers. Section 6.00, for
example, covers the entire range of "Winching and Towing." Within this large
chapter are smaller sections; 6.01 concerns wire rope, and the following
sections cover methods of splicing wire rope, storage of wire rope, etc.
In addition to arranging the book in this "outline" fashion, a complete
index can be found in Section 21.00.
Acknowledgements
Introduction
1.00 Mechanical Emergencies While Driving
Loss of oil pressure;
tire blowout;
broken axle or drive shaft;
boiling radiator;
broken steering linkage;
steering bent and ineffective;
headlight failure at night;
accelerator pedal stuck down;
brake failure.
2.00 Operating on Pioneer Roads
Examining the vehicle;
loading the vehicle;
introduction to the cab;
mechanical operation.
3.00 Avoiding Road Hazards
Four-wheel drive;
traveling in convoy;
tire chains;
loss of traction;
piled-up mud or solid obstacles;
log bridges;
capsizing;
fording and wading;
submerging.
4.00 Extricating the Vehicle
Stuck in mud or snow;
hung up in mud or snow;
hung up on a solid obstacle;
log bridges;
stuck while fording.
5.00 Procedures when Stranded
Leaving the vehicle;
water supply;
seeking help;
vehicle submerged.
6.00 Winches and Towing
Wire rope;
joining wire cable;
storage of wire rope;
types of rope;
synthetic fiber ropes;
knots for fiber rope;
nylon towing straps;
chain;
joining chain;
storage of chain;
chain repairs;
the winch;
selecting a winch;
installing a winch;
winch drive systems;
winch cable;
use of the winch;
anchoring the winch cable;
winching safety;
winding in the winch cable;
block and tackle;
recovery with a winch;
winching from a bridge;
removing a log under the car;
lowering with the winch;
using the winch for salvage;
salvaging a capsized vehicle;
salvaging a car from water;
towing a derelict;
attaching the tow cable;
overcoming mechanical drag;
towing a trailer;
trailer hitches;
extricating a stuck trailer.
7.00 Field Expedients
Capsizing and submerging accidents;
drive train expedients;
steering system expedients;
brake system expedients;
fuel system expedients;
tire expedients;
cooling system expedients;
electrical expedients;
problems in the primary circuit;
ignition system expedients;
engine expedients.
8.00 Check Lists
Cranking and starting trouble;
engine will not crank;
engine cranks, will not start;
engine starts, then quits;
low charge, dead battery;
poor spark;
low oil pressure;
engine uses too much oil;
steering problems;
front tires worn;
uneven tire wear;
vibration in drive train;
wheel bearings hot;
steering troubles;
brake trouble;
brake pedal sinks to floor; brakes do not hold;
brake pedal rises and brakes drag;
brakes drag;
car pulls to one side when braking;
brakes grabbing;
brake pedal does not return;
clutch and gearshift problems;
gearbox trouble;
clutch trouble;
rough running or conking out;
engine short of power;
engine conks out and will not restart;
engine overheats, radiator boils;
funny noises.
9.00 Tests and Testing Equipment
Cooling system tests;
engine tests;
clutch tests;
drive train and steering tests;
fuel system checks;
brake tests;
primary electrical tests;
ignition tests;
exhaust tests.
10.00 Shop Techniques
General shop hints;
axles;
differentials;
wheel bearings;
universal joints;
fuel system;
brakes;
adjusting the brakes;
bleeding the brakes;
relining the brakes;
the hand brake;
electrical repairs;
battery;
voltage regulator;
generator repairs;
light system repairs;
ignition repairs;
steering repairs;
tire and wheels;
repairs to springs;
repairs to shock absorbers;
cooling system repairs;
exhaust system repairs;
engine repairs;
valves;
engine removal;
miscellaneous engine repairs.
11.00 Body Repairs
Window glass;
roof dents;
chassis repairs.
12.00 A Shop Building
13.00 Diesel Engines
Diesel check list;
diesel engine tests;
diesel repairs.
14.00 Tools and Equipment
Tools for the car;
shop tools;
luxury tools and equipment;
a generator;
compressed air in the shop;
welders;
gas welders;
electric arc welders;
tools to make;
homemade test equipment.
15.00 Vehicle Modifications
Storage facilities;
body modifications.
16.00 Parts and Supplies
Supplies in the vehicle;
supplies in the shop.
17.00 Storage Facilities
Fuel Storage.
18.00 Preventive Maintenance
Greasing;
lubrication;
tune-up procedure;
radiator flush;
miscellaneous maintenance;
cold weather operation;
periodic checks;
check points;
daily checks.
19.00 Selecting a Vehicle
Vehicle types and sizes;
vehicle modifications;
vehicle comparisons.
20.00 Miscellaneous Formulas
Engine displacement;
weight on rear axles;
pulley ratios;
charts and measurements;
water measurements;
metric equivalents;
torque values for nuts and bolts;
battery electrolyte specific gravity;
metric equivalents.
21.00 Definitions and Index
1.00 MECHANICAL EMERGENCIES WHILE DRIVING
While a discussion of the disasters that await the novice driver on a pioneer road
may be a discouraging way to start a manual of this type, it is intended that
readers examine this section before they must face any of these problems, so
they can be fully prepared. This section is not concerned with such roadside
problems as flat tires, dead batteries, or running out of fuel. By "mechanical
emergencies" is meant the sort of trouble with the car that places its riders in
danger through lack of control of the vehicle or the threat of major damage to
the machinery. Many of the mechanical problems related here can be avoided
through attention to the items summarized in Section 18.00 on preventive
maintenance. Repairs to correct the problems listed here are described in
Section 7.00: Field Expedients.
1.01 Loss of Oil Pressure
Since oil, under pressure, is required to lubricate the many moving parts of an
engine, loss of this pressure is a major mechanical emergency. Stop the engine
immediately, or it will in all likelihood be permanently damaged. Once the
engine is safely stopped, look for the cause of the difficulty. Section 8.00 on
check lists may be of assistance in this search.
1.02 Tire Blowout
At the slow speeds that are common on pioneer roads, tire failure may not be
a serious problem. You will only hear a flopping noise and notice that the
steering seems unresponsive. At high speeds, however, a blowout can spin the
car out of control. The correct response to a blowout is to keep the foot off the
brake pedal or accelerator and try to steer the car to a safe stop. If a front tire
blows, the car will swerve toward the same side as the blown tire. Using the
brake will often cause a spin. With the transmission in gear the engine will slow
the car gradually, making it more likely that you will be able to hold the wheel
and steer to a halt.
1.03 Broken Axle or Drive Shaft
A two-wheel drive car propelled by only one pair of wheels will stop if an axle
or propeller shaft breaks; going up a hill it will roll back. In such a vehicle it is
necessary to make repairs before the car can proceed.
A 4WD car can continue as long as either the front or rear wheels are
functioning. If an axle shaft is broken in the rear end, for example, shift to 4WD
and attempt to proceed using only front-wheel drive. If a propeller shaft is
broken it should be removed before proceeding, or the stub end will flop around
and may damage the underframe of the car.
1.04 Boiling Radiator
A boiling radiator is indicative of an overheated engine, which may be caused
by any of a number of things as listed in Section 8.70 on check lists.
Do not shut off the engine if the radiator is boiling, for then all circulation of
water, even though the water is overheated, will be cut off. Put the transmission
in neutral and leave the engine idling. Very carefully open the radiator cap; live
steam is likely to be forced out under pressure, so it is advisable to cover the cap
with a thick rag for protection. With the engine still idling, slowly add enough
water to fill the radiator. Allow the engine to continue idling until the temperature
indicator returns to normal.
If opening the radiator cap reveals that the radiator is already full and additional
water is not needed, the engine is probably being overworked and slower speeds
and lower gears should be used. Alternatively, the thermostat may be blocked,
preventing the flow of coolant through the engine.
1.05 Broken Steering Linkage
In the event of breakage of any part of the steering system, it will probably
become impossible to steer the car, At low speed this may not be a crisis, but at
high speed it may not be possible to avoid a crash. Stop the car as quickly as
possible under such circumstances. The critical nature of the steering system
makes frequent examination a prime safety consideration.
1.06 Steering Bent and Ineffective
If a car strikes a tree stump, rock, or other obstacle in such a way as to bend part
of the steering linkage under the front end, the steering may become ineffective.
The two front wheels may point toward each other, for example. You will
usually be able to maintain enough control to stop safely.
1.07 Headlight Failure at Night
The obvious move in the event of headlight failure is to stop immediately. The
well- prepared driver will have a flashlight with which to seek the difficulty.
1.08 Accelerator Pedal Stuck Down
Mechanical failure sometimes results in leaving the accelerator pedal down,
rather than returning it when you release your foot. In this event the car will
continue to move. If you cannot lift the pedal with the toe of the foot, shut off
the ignition and brake to a stop.
1.09 Brake Failure
Before giving brakes up for lost, try pumping the pedal vigorously several
times. This may provide enough pressure to stop the car. If it does not, several
courses of action are open:
If the parking brake works, it can be used to stop the car.
If the parking brake does not work and if there is no steering lock incorporated
in the ignition lock, you can shut off the ignition switch, leaving the transmission
in gear. Engine friction will then slow the vehicle.
Alternatively, downshift to the car's lowest gear. This will bring the car
gradually to a slow speed. When the ignition is then shut off, the car will stop.
There are also occasions when terrain may aid in stopping the car. A swampy
section of road, for example, will serve this purpose, as will sand, deep snow,
or an uphill grade.
2.00 OPERATING ON PIONEER ROADS
Experience indicates that a number of factors contribute to successful operation
on pioneer roads. Among these are a knowledge of the individual vehicle, the
ability to load the car properly, and familiarity with the mechanical operation
of the car. These various factors will be considered before any discussion of
driving techniques.
2.01 Examining the Vehicle
Although it eventually becomes second nature, it is important to become
familiar with your vehicle and to examine it carefully before starting on a trip.
Know which side the differentials are on, since they are usually not centered.
The differential is the lowest point of the undercarriage on most cars. The driver
can gain a few extra inches of clearance over a rock or stump by placing the car
correctly over the obstacle, with the differential to the side. This allows the
higher side of the axle to pass over the obstacle.
See whether there is a protective plate under the front end to guard the steering
gear from obstacles. Such a plate is a good investment on a new vehicle. It
usually extends from the underside of the radiator housing back to the crankcase,
and on some cars covers the crankcase as well.
Know how wide the car is so that clearance between trees, rocks, or other
obstacles can be accurately judged.
Know how far apart the tires are, especially in an area where log bridges are
common. At first it is advisable to get out of the car when approaching a log
bridge to be sure that you have estimated correctly before proceeding. (See
Section 3.06.)
aom6.gif (486x486)
Know how high the top of the truck or the load is. This is important in relation
to overhanging branches.
Beyond the dimensions of the vehicle, there are other mechanical details that
should be examined before departing:
In areas with poor bridges, remove the cab doors if this is at all practical. The
author and many of his friends have been saved from drowning by this simple
expedient. If the cab has no roof, of course there is no need to remove the doors.
On some vehicles it is possible to remove the top half of the door, leaving the
lower half in place. Seat belts should be used to prevent the occupants from
falling out of the car.
Be sure that the fuel tank is full before starting, even on a short journey. Even
in familiar territory it is quite possible to get stuck and work all day to get free.
If there are racks for additional fuel or water cans, be sure that they are full before
starting.
Check to see that oil, battery, radiator, power steering, and brake fluid reservoir
are full.
See that the brake pedal does not feel spongy or sink to the floor, and that the
hand brake will stop the car if necessary.
Be sure that there are enough spare tires to get where you are going, or have the
tools and patches to make repairs on the road if necessary.
Examine the toolbox to see that it contains appropriate tools and spare parts.(See
Section 14.10.)
2.02 Loading the Vehicle
The two most important factors in loading are the total weight of the load in
relation to the capacity of the vehicle and the distribution of the load over the
chassis.
The driver's manual for the vehicle will indicate the total load allowable. For a
small car, the weight of the driver and any passengers may make up a large part
of the total load. A full fuel tank may add 75 to 150 pounds (34 to 67 kilograms),
and a spare five-gallon (19 liter) fuel can adds an additional 40 pounds (18
kilograms).
aom1.gif (600x600)
As a very rough rule of thumb for overloading, there should be some free
movement between the axle and the chassis. The chassis should never rest upon
the axle without any reserve in the springs.
In balancing the load, spread the weight as evenly as possible between the front
and rear axles. Concentrated weight on the front portion of the load box in a
pickup truck, for example, may break the chassis even though the load does not
exceed the maximum allowed in the driver's manual.
Weight placed halfway between the front and rear wheels will be supported
equally by each axle. If all the weight is over the rear wheels, the rear springs
and axle housing may be overloaded. If all the weight is concentrated behind the
rear wheels, the front end will be lightened; it may even leave the ground,
making steering impossible.
Formulas are presented in Section 20.00 for the mathematical calculation of the
load on the rear wheels, although this is not necessary if common sense is used
in load distribution.
If there is a choice of vehicles for a given load, use the one that will give the
lowest center of gravity. That is, the one that will carry the load nearest to the
ground. A pickup truck carries its load between the rear wheels, for example,
while a stake body truck carries the load above the rear wheels. The result is that
a pickup truck is more stable and less likely to capsize than a stake body truck
of the same size.
Similarly, keep the heavy part of a load as low as possible in the truck. If the load
is too high it will make the vehicle top-heavy. When a truck must of necessity
be loaded so that it is top-heavy (for example, with a large machine), be very
careful on roads with excessive crown or tilt to avoid capsizing the vehicle.
The load should not be allowed to hang out of the sides of the vehicle if this can
possibly be avoided, since a hazard will be presented by trees, branches,
buildings, and other vehicles.
After loading, be sure that the load is secure and cannot shift even if the car
lurches severely. A load that shifts forward may injure the driver; if it shifts back
it may fall out of the vehicle; if it shifts to the side the vehicle may be turned over.
Tie the load to the car with ropes or ratchet straps with hooks on the ends, sold
for this purpose. Tires that do not contain steel strands can be cut into long elastic
straps with great strength for securing loads. Fastening the load tightly is
especially important in the case of a small vehicle carrying a relatively large
single unit such as a drum of fuel. A great deal of damage can be done by such
a drum if it "gets loose" in the back of a pickup truck.
2.03 Introduction to the Cab
Before starting the engine, take a moment to familiarize yourself with the cab.
Many drivers believe that on pioneer roads speeds are so low that seat belts are
not necessary. Experience will show, however, that they are a great asset. While
there may be no danger of a collision in an area with very few cars, the seat belt
can keep you from hitting your head on the cab roof on a rough road, or from
falling out of the car if the doors have been removed.
One of the best safety rules for driving on rough roads is to keep the thumbs
outside the rim of the steering wheel. Although unnatural at first, it soon
becomes second nature, and if the steering wheel is wrenched away by striking
an obstacle, the spokes cannot injure or dislocate your thumbs. This practice is
not required on vehicles with power steering, but few true frontier vehicles are
fitted with power steering, which adds to the complexity and cost and offers an
unneeded opportunity for mechanical failure.
Hold the steering wheel with the hands in a position corresponding to the
position of clock hands at ten minutes past ten. Two-handed steering is essential
if roads are rough, and this position gives the best leverage for a turn in either
direction.
In a snowy or rainy climate where the driver's feet will often be wet, remove the
rubber pads from the pedals. The rubber will become very slippery when wet,
making it hard to keep the feet on the pedals. (See Section 15.20.)
Although many cars advertise that three people can be accommodated in the
front seat, it is much safer to carry only the driver and one passenger. This allows
more room for the operation of the gear shift and the transfer case, and it is much
easier for two people to get out of an endangered car in a hurry than it is for a
third person sitting in the center of a bench seat.
2.04 Introduction to the Drive Train
Before starting off, a few words about the mechanics of the car are needed.
In an age where most sedans have automatic transmissions, many people are not
familiar with the gear shift and clutch, or with their function. The gear shift is
intended to allow the engine to operate at optimum speed regardless of the speed
of the vehicle, since a gasoline engine develops very low power at low speeds.
Thus in first gear the engine is turning rapidly but the wheels turn slowly; in top
gear the engine and wheels are generally turning at the same speed.
The clutch separates the engine from the wheels for a moment so that the gears
can be shifted. A clutch resembles two flat discs, one of which is connected to
the engine and the other through the gearbox to the wheels. When the discs are
separated, no power is transmitted to the wheels. When they are pressed
together, the engine power is sent through the two discs to the wheels.
In order to shift from one gear to another, it is necessary to first depress the clutch
pedal. This will disconnect the engine from the wheels so that the car is coasting
freely. The shift can then be made, and the clutch released to apply power again.
This process of clutching, shifting, and unclutching should not be hurried; the
result is rapid clutch wear or even broken axles.
DOUBLE CLUTCHING is needed to shift from a high gear to a lower one.
While synchromesh transmissions have made double clutching less critical and
even unnecessary in some circumstances, the technique is still a great wear-saver
for any gearbox. Double clutching allows the engine and the gearbox to
be matched in speed before the gears are engaged. If this were not done, the gears
would "crash," or grind against each other until they were meshed by force.
Double clutching is not at all difficult, but it does require some practice. It cannot
be taught from a book, although some suggestions will be presented here for you
to try in practice sessions.
Suppose it is necessary to shift from second gear down to first gear in order to
slow the car going down a hill. With the car moving across the top of the hill in
second gear, press the clutch down. Put the gearshift in neutral and let the clutch
up. The engine is now connected to the gearbox, although the gearbox is in
neutral and not transmitting any power to the wheels. Accelerate the engine until
its speed approximates the speed at which it would be running if the car were in
first gear. Then quickly press the clutch down, shift gently into first gear, and let
the clutch up. If the estimate of engine speed is accurate, the spinning gears in
the gearbox will be going at the same speed as the wheels, and will mesh without
crashing.
Double clutching should become the natural way to get into a low gear when
descending a bill. Use of the brakes will cause overheating and failure, possibly
at a crucial time. In addition, braking on a slope can start the car sliding out of
control.
THE TRANSFER CASE is actually another gearshift added to the main gearbox
to obtain even lower gear ratios. At these lower ratios the engine turns at high
speed, thus developing peak power, while the wheels turn very slowly. In most
4WD cars the transfer case approximately doubles the overall gear ratio,
meaning that the car travels only half as fast in low range as in high range.
The regular gearshift is used in the normal way in low range. If the vehicle can
be accelerated to top gear in low range and you want to go faster, it is necessary
to shift both levers. First shift the transfer case to high range, then put the
gearshift into the appropriate gear. It may also be necessary to engage the front-wheel
drive after shifting the transfer case. The whole shift may take so long that
momentum will be lost, and the regular gearshift will probably have to be put
into the first gear even though it is a lower ratio than top gear in low range.
2.05 Introduction to the Engine
For those who are not familiar with the basic principles of automotive engines,
the following basic introduction may be useful:
Energy to move the car is derived from fuel, usually gasoline, which must be
mixed with air to make it burn, and then must be burned in a controlled way so
that the energy can be used.
Gasoline is stored in the fuel tank. From there it goes through tubing to a small
pump, which forces it into the carburetor. At the same time, air is sucked through
the air cleaner where dust and solid particles are removed, and into the
carburetor. In the carburetor the fuel and air are mixed to a combustible vapor.
This vapor is then sucked through the intake manifold to the engine itself. At the
engine, the fuel vapor passes through a valve at the top of each cylinder, where
it is sucked into the cylinder when the piston within it moves down, creating a
vacuum inside the engine.
Some gasoline engines have no carburetor. Air is drawn into the cylinders by the
action of the piston, and fuel is sprayed into the cylinders by injectors similar
to those in a diesel engine. This "fuel injection" system is not commonly found
on frontier vehicles because of its complexity and intolerance of poor fuel
quality.
aom2.gif (600x600)
The engine operates on what is termed a four-stroke cycle. The four strokes are
intake, compression, ignition (or power), and exhaust. On the intake stroke of
a piston, the cylinder is filled with fuel vapor through the intake valve. As the
piston reaches the bottom of the cylinder the intake valve closes, and the piston
starts up again. The fuel vapor is thus compressed, cramming more energy into
a smaller space. As the piston passes the top of its stroke, the space within the
cylinder is smallest, and the fuel mixture is ignited by a spark from the spark
plug. The fuel explodes violently, but since both valves are closed there is
nowhere for the energy to go unless the piston is forced downward. This is the
power stroke, and it is the energy of the explosion forcing the piston downward
that turns the engine and makes the car go. The fourth stroke, exhaust, serves to
force the used gases out the exhaust valve to clear the cylinder for the next cycle.
In order to keep this cycle moving, several extra parts are essential. The
generator, which is turned by the engine, provides electric power to keep the
battery charged for the operation of electric accessories such as headlights,
windshield wipers, and the horn. The battery also provides power to the ignition
system of the car; 12-volt power from the battery travels through the breaker
points to the spark coil. There it is built up to a very high voltage, which is sent
through the distributor to each spark plug at precisely the right time to ignite the
fuel mixture at the top of the compression stoke.
The cooling system keeps the heat of the explosions inside the cylinders from
damaging the engine. It consists of a radiator, fan, water pump, and a supply of
cooling water which runs through little channels inside the engine block. The fan
blows air through the radiator to keep it cool, and water flowing through the
radiator is therefore also cooled as it circulates around its path through the
engine, water pump and radiator.
There are several other accessories that are not strictly essential to the operation
of the engine, but are useful or even vital parts of the car. The lights, windshield
wipers, dashboard gauges, and speedometer fall into this category. The drive
train has been discussed in Section 2.04, together with the principles of its
operation.
Also essential, although not closely related to the work of the engine, are such
frame parts as the chassis, upon which the car parts are mounted. On the chassis
are the springs, which support the weight of the vehicle on the axles; the shock
absorbers, which smooth out some of the road bumps; and the brake system,
which stops the car. The steering system, also mounted on the chassis, is another
separate entity that is essential to the operation of the car.
Each of these parts and systems is discussed in some detail in other section of
this book. Refer to the index at the back of the book for a complete list of the
various parts, their functions, and how to test and repair them when necessary.
3.00 AVOIDING ROAD HAZARDS
Having devoted some time to checking the vehicle, you can safely start on your
journey. The difficult process of pulling a car out of a swamp or broken bridge,
or removing it from a projecting rock or stump, can be eliminated by avoiding
road hazards of this type. Knowing what to do in advance can save a great deal
of time and effort.
aom3.gif (600x600)
The most common road hazards involve loss of traction,
being hung up on the chassis, log bridge failures, capsizing, fording, and to a
lesser extent, submerging. The following sections will illustrate in some detail
how to avoid each type of problem.
STRADDLING OBSTACLES such as potholes, rocks, and logs is a simple
technique, and yet few drivers who are accustomed only to wide paved roads
readily adapt to driving over an obstacle. All that is needed is a quick judgment
of how large the obstacle is and whether the car will pass over it without falling
in or getting hung up. If the car will pass, go over the obstacle rather than trying
to pass around it. Going around an obstacle on a narrow pioneer road generally
means going off the road, which is not usually a good practice.
RUTS AND GULLEYS can also be straddled in the same way. Often rain will
wash a deep gully down the middle of the road or a hill, since that is the lowest
part of the track. It is frequently safer to straddle this gulley than to go to one side
of it and be forced off the road. Careful evaluation of a long gulley is necessary
before starting over it, since it may widen farther along its course, trapping the
car.
GRAVEL ROADS pose their own special problems. Although they are usually
more passable in poor weather than dirt roads, the loose gravel is a hazard. Speed
should be kept to 35 miles (55 kilometers) per hour or less because of the damage
that can be done by flying gravel. When passing another car speed should be
further reduced. In many areas it is common practice to cover the glass lenses
of headlights with cardboard or heavy screening for daylight driving.
TAKING A HELPER is always good practice on a pioneer road. Even in a
vehicle equipped with a winch, having another person with the driver makes it
much easier to get the car out of trouble. A helper can make sure the car is lined
up on a log bridge, can check to see that a suspicious rock will not hit the oil pan
or steering gear, and perform similar duties. In many parts of the world it is
possible to get such assistance in exchange for a ride.
DRIVING AT NIGHT should be avoided, especially in an unfamiliar area.
When it is absolutely necessary, take a good flashlight in addition to any other
necessary tools and supplies. If the car's lights seem very dim, check for mud
or dust on the lenses. If allowed by law, it is often useful to add extra driving
lights; they should be protected from branches and other obstacles.
A WORD ON BRAKES: Stopping the car with all four wheels locked up and
not turning, although spectacular, is not the quickest way to stop. You also lose
steering ability, since the front wheels can only be steered if they are turning. The
best method, although it requires practice, is to use as much pressure on the brake
pedal as the wheels can take without locking up. If they do skid, too much
pressure is being applied.
When driving on mud or snow where traction is poor, continuous application of
the brakes will send the car out of control. Under such conditions you can either
steer or brake, and therefore must alternate between the two. Pumping the
brakes is a good compromise: when the brakes are applied, the car slows but is
unsteerable; when the brakes are released the car can be steered, but is not being
slowed.
3.01 Four-Wheel Drive
The most common method of avoiding or overcoming road hazards is through
the use of four-wheel drive. As the name indicates, this system provides power
to all four wheels of the car, not just to the rear or front wheels as is generally
the case with sedan-type automobiles. Any vehicle used for rugged driving is
generally equipped with four-wheel drive.
When traction is a problem, such as driving on snow or mud, tire chains are
commonly used. Tire chains, on the rear wheels or on all of the wheels, add
significantly to tractive power on slippery roads. They are considered in Section
3.03. Improved traction can also be obtained with a limited-slip differential.
This device is available on most cars as a factory option. It supplies power to the
wheel with the best traction. While it does add to reliability, a limited-slip
differential offers some special maintenance problems, and is therefore not a
universally accepted device.
At least one vehicle, the German Unimog, provides differential locks that
eliminate the slipping ability of the differential. As a result all power is
transmitted to the tire with traction, even if only one tire has traction at the
moment.
Four-wheel drive should be engaged only when it is needed. The practice of
leaving a car in 4WD just because it might be necessary somewhere down the
road greatly increases tire wear and may also damage the drive train. This is
because all four tires are being moved under power, but the tires are not exactly
the same size due to tire wear and differences in tread thickness and inflation
pressure. The larger tire will go farther with a single revolution than the smaller
one, and one of the two will have to be scuffed along to make up the difference
between front and rear axle speeds. This scuffing wears away the tread, and if
the road is hard and dry so that the tires cannot scuff, the drive train may be
overworked and fail.
Experienced drivers will run in two-wheel drive until they see an obstacle ahead,
then will shift to 4WD without stopping. Because the car is still moving at a good
speed, the momentum may carry the car through the obstacle, with the help of
the doubled traction that results from engaging the front wheel drive. Once past
the obstacle, two-wheel drive can be resumed.
Some 4WD vehicles are equipped with constant four-wheel power supplied
through a gearbox similar to a differential. This system allows for variations in
tire size, eliminating dragging or scuffing and resulting tire damage. It also
eliminates the need for a control lever to engage the front wheel drive. This
system is more commonly found on luxury touring cars.
3.02 Traveling in Convoy
An excellent way to avoid getting stuck, or to simplify the process of extricating
a stuck car, is to travel with two or more vehicles in a convoy. Each car can help
the other, either pushing or pulling a stalled vehicle through difficult areas. If
a car must travel on a poor road without a winch, having another car along with
a winch is almost as good as having its own.
It is usually advisable to send the more experienced driver first when going in
convoy in order to show the best way over or around obstacles. His chances of
getting through a difficult area are improved by his experience, and if he passes
and the following car does not, he can tow it through.
When different sizes of cars are traveling in the same group, the drivers should
consider which one to send first. In deep snow, mud, or swamps, for example,
the larger car should be sent through first. Its greater road clearance gives a
better chance of getting through, and it can then tow the smaller car if it gets
stuck. If the smaller car went first and got stuck, it would be necessary to pull
it out backward (unless it had a winch) and then send the bigger car through.
On a bridge of questionable strength, send the small car first. A weak bridge may
carry the smaller car where it would collapse under the larger one. The driver
of the small car can evaluate the larger car's chances as he crosses.
3.03 Tire Chains
A great aid to getting through slippery areas is the use of tire chains. Chains are
excellent in mud or snow, but provide a very rough ride on a smooth or hard road.
They are a nuisance when they must be put on and taken off frequently to allow
for alternating sections of good and poor road.
On very poor roads or where no roads exist, chains on all four wheels and the
use of 4WD will provide a tremendous increase in tractive power. Tire chains
should never be used on only two wheels if four-wheel drive is used. The
difference in effective circumference of the tires with and without chains will
cause tremendous strains to the car's drive train, which may damage the vehicle.
The best type of tire chains has V-shaped bars welded across the links that run
around the driving surface of the tire. This bar gives both added strength and,
more important, added traction.
The most important consideration for long life of tire chains is a good fit on the
tire. The chain should be so tight that it cannot slip when the wheel turns. The
springs or rubber circles used to pull the chains tight are not meant to hold loose
chains in place. If necessary these spreaders can be supplemented with loops of
inner tube rubber. To pull the chains tight, many drivers deflate the tire
somewhat, fasten the chains as tight as they will go, and then inflate the tire to
proper pressure. Another some what easier method is to put the chains on as tight
as possible, then drive around a bit until they have "settled in." This should not
take more than a few hundred feet (100 meters), then the chains can be pulled
up again. It is surprising to see how much slack is left in the chains even though
they were tight when applied. Similarly, it is good practice to stop periodically
and check that the chains are tight while driving. They should never slap the
fenders, exhaust pipe, or any other part of the car.
Driving with tire chains when they are not needed causes severe wear. If used
on a hard-surfaced road, for example, the chains will soon be ruined by the
friction and beating action.
3.04 Loss of Traction
Perhaps the most commonly faced hazard on pioneer roads is loss of traction.
Slipping can be caused by mud, snow, ice, wet leaves, or similar surface
conditions, or it can be related to another problem. For example, a car might be
hung up on a rock and have the double problem of being anchored to the rock
and having insufficient traction to pull off.
Driving on mud is very similar to driving on snow, except that mud offers much
higher resistance to the passage of a wheel than snow does. In computing the
rolling resistance, a measure of the retarding effect of a road surface to forward
movement of a vehicle, the following formula is used:
(gross weight of vehicle, pounds or kgs) x (road factor)
-------------------------------------------------------
1,000
= rolling resistance (in lbs or kgs)
In this formula the following figures may be used for the "road factor":
good concrete road, 15
2 in (or 5 cm) of snow, 25
4 in (or 10 cm) of snow, 37
smooth dirt road, 25
sandy dirt road, 37
mud, 35 to 150, depending on type and depth
soft sand, 60 to 150
Obviously in a practical situation a driver will not stop near a swamp and get our
the calculator to figure what the rolling resistance will be. On a theoretical basis,
however, from these figures it is evident that the resistance of mud is as much
as six times as great as that of two inches (5 cm) of snow. To overcome the
resistance, the driver will need to use lower gears or other tractive aids.
A little experience will indicate that different types of mud have different effects
on the car. Some mud may be recognized by a distinctive color or appearance.
The driver will learn to be prepared for deep, thick mud, a slippery hill, or some
other difficulty solely by the appearance of the mud's surface.
To avoid getting stuck, a good basic rule is never to do anything suddenly while
driving on a slippery surface. Brakes, accelerator, or steering, if suddenly
applied, will usually result in a spin or slip. As a mental guide, it is often useful
to pretend that there is a drinking cup sitting on the front of the car, full to the
top with water. The goal is to drive the car without spilling a drop.
If the car does skid in mud or snow, keep off the brake pedal. It will only make
the skid worse. Instead, gently press the accelerator and steer in the direction in
which the car is sliding. This may not be the desired direction of travel, but as
soon as the car is under control it can be slowed and turned.
In an area where loss of traction is a frequent problem, it is useful to carry a piece
of burlap, canvas, or expanded metal to lay in front of a spinning tire. Planks are
often used in the same way, but are less convenient to carry.
To avoid getting stuck in a swamp or mud hole it may be worth the effort
required to cut leafy branches or sticks to throw in before attempting to cross.
Branches, rocks, planks, sticks, sand, thick grass, or any other material that will
increase traction may take less time to gather than would be required to pull the
car out if it got stuck.
Inertia can be a great help in getting through a slippery area. If hills and swamps
alternate, as is often the case, a driver can build up speed going downbill and
drive into the swamp as fast as possible. The car will rapidly lose speed in the
mud, but the inertia may carry it through. In any event, it will get farther than if
the car had entered at slow speed. This method is rough on the car, and should
never be used if a solid obstacle such as a rock or stump may be hidden in the
mud, since it could rip the front end of the car apart. There is no way to get up
any speed in an area where the hills are also slick, so under such circumstances
this method is of no value.
STOPPING THE CAR can also be a problem where traction is low. Rather than
use the brakes, which will generally cause the car to spin or slide, shift the
transmission to a lower gear to slow down. If the car must be stopped, pump the
brakes up and down.
ON A STEEP HILL with poor traction a car may slip downward with all four
wheels locked. This may be forward, sideways, or backward, or the car may spin
slowly around as it goes down. The same aids that are useful for moving will also
help to stop: tire chains, leaves and branches on the road surface, etc. Another
great help in such a situation is the "Block," which increases the area exposed
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to the slippery surface. The Block is nothing more than a large piece of timber,
perhaps with a handle cut into one end, which seems to be a universal piece of
equipment for driving on a poor road. It may be called a chock or wedge, or any
of a hundred names in other languages, but it is found in any part of the world
where pavement has not yet reached--and some where it has.
3.05 Piled-Up Mud or Solid Obstacles
Another obstacle caused by mud is the retarding effect when the chassis of the
car sinks deep enough to get hung up on the road surface. This is a special hazard
for cars with small tires and, consequently, a low frame.
If there are no rocks or stumps in the mud, the inertia principle described in
Section 3.04 can be used to carry the car though the deep mud, or at least well
into it.
Asking the passengers to get out before a deep swamp will lighten the load, and
may help to avoid getting stuck. There is much to be said for the universal
driver's slogan, "Everybody get out and push!" Getting out decreases the load
and raises the frame of the car; pushing increases the tractive effort.
If the other vehicles using the road are of similar size to your own, it is usually
best to stay in the ruts on a very muddy road. The mud in the ruts is likely to be
packed somewhat by earlier passages.
To avoid getting hung up, especially in a small car, it may be better to get off the
road altogether under some circumstances.
Avoiding getting stuck in deep snow may be somewhat different. Often the snow
is piled higher than the hood of the car, so that the problem is not merely one of
getting hung up on the chassis. It becomes necessary to push the car into the
snow, and the traction may not be adequate. The snow must be removed in such
a case. This is usually done with a plow or blower mounted on the front of the
vehicle.
In snow less than two feet (1/2 meter) deep, the principles used for driving in mud
apply.
Avoiding getting hung up on rocks, stumps, and other solid obstacles is more a
matter of judgment than power. Usually such obstacles are large enough to
prevent passage, and one cannot simply push through without damaging the car.
Keeping the car moving, then, means going around such obstacles if the car
cannot pass freely over them. If there is any doubt, always get out and check.
3.06 Log Bridges
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Probably the most common type of bridge on a frontier road consists of parallel
logs laid across the stream. Generally there are three logs. One is on one side of
the bridge, and two are on the other side. Both large and small vehicles will use
the single log on one side, the inner of the double logs is arranged to fit the
smallest vehicle likely to use the road, and the outer log will accommodate
larger vehicles.
Avoiding getting stuck on such a bridge is largely a matter of getting lined up
straight before starting across. While experience may allow some drivers to
charge across without slowing down, the novice will do better to stop and check
first. By sighting along the line of the logs it will be possible to determine
whether the tires are properly lined up. Some drivers carry a piece of string for
lining up bridges. One end of the string is held at the far end of the bridge and
the other end at the back tire of the car; it should line up with the entire length
of the log and the front tire of the car as well. (See Figure 3.06),
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When you are sure that the car is lined up, shift the car into 4WD, but not low
range. Move across the bridge as quickly as possible, so that inertia may carry
the front wheels across even if the rear ones slip off or the bridge collapses. In
such an event, the front wheels will often be able to pull the car across if they
have reached the other side.
Once practiced, the crossing of a bridge of this type becomes quite routine, and
the driver will learn to judge from some distance a rotten log or one that may slip
sideways. If the capacity of the bridge is in doubt, it is usually advisable to ask
passengers to walk across, thus lightening the load on the bridge and perhaps
sparing them a dunking.
When crossing a bridge while towing a trailer, bear in mind the added length of
the combined vehicles and do not stop before the trailer is fully across the bridge.
(See also Section 6.80 on driving with a trailer.)
One of the most common problems with log bridges, other than collapse due to
rot or overloading, is the separation of the logs. This allows the tires to slip off
of the logs, trapping the car. This can be prevented by proper bridge design,
anchoring the logs with stakes or large rocks at the ends. A driver approaching
a bridge that looks like its logs may separate can usually save time by fixing the
bridge before trying to cross. If the logs do drop the car, the bridge will have to
be repaired anyhow.
3.07 Capsizing
A driving trauma to which many drivers may be unaccustomed is tipping over.
This may occur due to the road surface or the way in which the vehicle is loaded,
or both.
A vehicle body style in which the load is carried high, such as a stake or platform
body, is inherently less stable than one where the load is low, such as a pickup
body. (See Section 2.02.) Luggage racks on the roof will add to the tendency
to roll over.
Capsizing can also result from the angle of the road. On a slick hill with a drop
at the edge, for example, try to keep the car away from the ditch. If two wheels
on one side slip into the ditch, even though it may not be very deep, the car is
likely to roll over. The inertia built up in sliding into the ditch will help to carry
the car over onto its side.
Being unaccustomed to pioneer roads, some drivers feel insecure on them. If a
car feels as though it is about to tip over, it is often helpful to get out and look
at it from in front or behind. Generally it feels worse than it looks, and a quick
check will reassure the driver.
Some drivers tie a length of string with a small weight on the end--a stone or
washer, for example--to some convenient part of the dashboard where it can
hang down freely. As the car starts to tip the driver becomes familiar with how
great an angle between the string and the floor represents a danger point.
For the novice, it may even be worth tipping the car intentionally just to see how
far it can go before capsizing. The learning experience may save a lot of grief
and anxiety later. Fortunately speeds on pioneer roads are low, so that there is
no great danger to life from capsizing. The most notable exception would be a
mountain road, where a great drop may be involved.
Although this section has emphasized techniques to be used in avoiding
capsizing, there is an important point to remember if capsizing is inevitable:
Shut off the engine. As the car rolls over, oil will be drained away from the oil
pump intake, the engine will get no lubrication, and it will risk freezing up. After
capsizing, of course, the first concern is the physical safety of the occupants.
After that, reference may be made to Section 7.00 on field expedients for advice
on restoring the car.
3.08 Fording and Wading
Because of construction problems, many frontier roads may not have bridges
over minor streams. Cars are expected to ford the water, which is not common
practice in areas where paved roads are the norm. Getting stuck while fording
presents extra problems, and extra care is warranted to avoid stalling.
If unfamiliar with a ford area, stop and get out for a check before driving
through. Walk through the water if possible on the same route the car will
follow. The bottom should be relatively firm and free of large rocks. There
should be acceptable entrance and exit paths. The current must not be strong
enough to carry the car off, and the water should not be too deep. The allowable
depth will be governed by the size of the car. Knee deep or slightly more is
usually the greatest depth that a small car such as a jeep or land rover will cross
safely. A larger truck will be able to go proportionately deeper.
If the water will be deep enough to wet the fan blades, loosen the fan belt
temporarily while crossing, so that the fan does not turn. This will keep the
ignition system from getting sprayed and drowned. Of course, the fan belt must
be tightened immediately after crossing the ford.
If the car has a clutch housing plug, as the Land Rover does, be sure it is in place
before entering the water. This plug drains moisture from the clutch housing
when it is removed, but the clutch would be "lubricated" by the water and the
bearings would be corroded if the housing were full of water.
While fording, keep the left foot lightly on the brake pedal. This will keep water
from getting between the brake shoes and the drums, which would lubricate the
brakes and make them useless. Disc brakes, available on some 4WD cars,
greatly reduce the problem of water lubrication.
Drive the car slowly through water, since high speed will result in water being
thrown up by the wheels which will drown the ignition system and stall the car.
A diesel-powered vehicle such as the Unimog or a diesel Land Rover offers the
advantage of having no ignition system. It is consequently much more reliable
for fording than a gasoline engine.
If current in the stream threatens to wash the car downstream, attach the winch
cable to a tree on the other side before starting across. If there is no winch on the
car, put a wire cable across the stream along the down-stream side of the ford
area to act as a guide for the car. This cable should be securely anchored to trees
or rocks on each side.
After completing the ford, check to see that the brakes are working. If they have
become wet and are ineffective, hold the brake pedal down lightly while driving;
the heat will dry the brake linings and restore stopping power.
If the fan belt gets wet while crossing it may slip and fail to cool the radiator or
turn the generator. For a quick check, look at the ammeter. If it shows a discharge
rather than a charge, the belt is probably slipping. Stop and dry the belt with a
rag.
Fording with a trailer can be simplified by unhitching the trailer and sending the
car across first, then towing the trailer across with a length of wire rope.
If the water is deep enough to cover the exhaust pipe, the pressure in the exhaust
system may reduce engine power or stall the engine. Once the engine has
stopped the water pressure will make it virtually impossible to restart, and the
car will have to be towed out.
If a car is driven into water that is too deep, or where the bottom is unsatisfactory,
it may stall or capsize or both. Stalling on land is of little consequence, but in
water it may be a serious matter. Extra attention to fording is therefore
worthwhile.
3.09 Submerging
Submerging accidents may result from a broken bridge, a ford that is too deep,
or from slipping off an adjacent road into deep water. In all of these cases the
accident can be avoided by the exercise of sufficient care.
As outlined in Section 2.01, it is well worth the trouble to remove the doors if
a submerging accident is even a remote possibility. This simple expedient can
be a real life-saver.
If submerging is inevitable, it is important to shut off the engine before it goes
under water. This will prevent the pistons from drawing water into the cylinders
and trying to compress it as they do the gas-air vapor. Water cannot be
compressed, and the engine will be ruined in the attempt.
If there is time, it is advisable to shut off all electrical accessories that may be
running: lights, radio, windshield wipers, electric fuel pump, etc.
See instruction in Sections 5.01 and 7.20 regarding recovery and restoration of
a submerged vehicle.
Although most drivers would be reluctant to experiment, it is interesting to note
that the classic Volkswagen "Beetle"--one of the most widely distributed
vehicles on earth--will float in water for a short time if lightly loaded. Opening
a door, however, lets the water in and sinks the car, so it is necessary to escape
through a window.
4.00 EXTRICATING THE VEHICLE
No matter how carefully they may try to avoid hazards, even the best drivers will
find that on some roads there are obstacles that cannot be passed by ordinary
means and the car becomes stuck. This section presents a number of suggestions
for getting out of difficulties involving mud, rocks, log bridges, and other
hazards.
The first step when the vehicle is stuck is to consider what resources are
available. The greatest asset is probably a winch. There are few problems that
cannot be remedied with this all-purpose tool, since it can move the car without
traction. The uses of the winch are so varied that an entire section (Section 6.00)
has been devoted to its operation.
Even lacking a winch, however, there are many things that can be done to
extricate a car before it is necessary to give up and send for help--if any is
available.
A SHOVEL is a very basic tool, and should be a part of the equipment carried
in the car if mud, sand, or snow must be crossed.
EXTRA JACKS provide tremendous power, although the travel they can
provide is limited to a few inches in most cases.
PLANKS can be used as levers, hole fillers, mats to provide traction, etc. They
make good platforms for jacks, which otherwise may slip and drop the car.
A BLOCK AND TACKLE can multiply a person's pulling power several times,
and there are many types of ratchet hoists and similar devices that can be used
to move a stuck vehicle in much the same way as a winch except that they are
hand powered and do not have the speed of a winch.
ANIMALS are often overlooked as a source of rescue power. The kind of
animals available will vary widely from one area to another, but any animal that
can pull a plow should be capable of pulling a car if necessary. In areas where
human labor is inexpensive and plentiful it is often possible to gather a group
of people to haul on a towrope for a small fee, or even for no charge at all if motor
vehicles are enough of a novelty.
WELD A HOOK onto a wheel for use in an emergency as a replacement for
natural traction. Weld the hook in such a way that it would be inside the tire if
a tire were fitted to the wheel. When stuck, jack up and remove the slipping
wheel and replace it with the prepared wheel. Attach a rope to the hook on the
wheel and attach the other end to a solid anchor such as tree or rock, in front of
the car. Drive the car forward, letting the hook hold the rope and wind it onto
the wheel like a winch. (See Figure 4.00a)
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FIBER ROPE can often be wrapped around a tire in much the same manner. The
trick is to drive the car along the length of the rope until it is out of the difficult
area. With wide tires this is not difficult, and is a very satisfactory way of
extricating the car. (See Figure 4.00b.)
aom8.gif (486x486)
A POOR PRACTICE is that of attaching a rope to the propeller shaft to get
pulling power. The shaft was not meant to handle a pulling load from the side;
it is intended only to transfer a twisting motion from the gearbox to the
differential. The use of a propeller shaft in this way may bend the shaft or
damage the universal joints.
STURDY VINES can often be used as ropes if not enough manufactured rope
is available. Generally the vines should be twisted to separate the fibers at the
point where a knot is to be made, or else the vine will break. In many tropical
areas there are vines that will serve very well as towing cables, taking a
surprising amount of strain without breaking. Residents of the area will
probably know which vines are useful for this work.
TWO-WAY RADIO is not a resource in the same way as the other items listed
here, but it is a great aid in many cases. With it advice can be sought, and if the
car cannot be extricated the radio can be used to send for assistance. Where radio
is in common use in this manner, everyone seems to make check calls on the
hour, with resulting confusion and jammed frequencies. A much more satisfactory
arrangement is to make check calls at some less common time, perhaps 20
minutes after the hour.
4.01 Stuck in Mud or Snow
Cars get stuck in mud or snow in two basic ways: They either lose traction on
a slick surface or become bogged down when the frame is hung up. A
combination of both is also common. This section considers the loss of traction.
Since 4WD increases traction and eliminates "dead" wheels, the problem of loss
of traction is most commonly faced on a hill. In flat areas the 4WD will usually
overcome lack of traction, especially if used with tire chains on all four wheels.
A hill requires greater traction than flat ground.
If a car slips while trying to climb a hill, it may be useful to remove some of the
load from the vehicle and make another attempt. As outlined in Section 3.05,
there is a reason why most foreign drivers soon learn to say "Everybody get out
and push!" in the local language. This method, though admittedly primitive,
lightens the load and increases the traction.
Spinning the wheels in an effort to get out of a muddy or snowy spot will rarely
do any good at all. The temptation is to use a heavy foot on the accelerator; it
often seems that sheer power should get the car out. This is not the case,
however. The spinning will soon overheat the tires, bonding the inner tubes to
the tires, melting the inner tubes, or even setting fire to the tires. A little
experimentation will reveal that the greatest traction is obtained by creeping the
car out of such a spot as slowly as possible so that the wheels stick to the surface
rather than spin.
Another technique of little value in an extended swamp, muddy hill, or snowy
area is rocking the car back and forth, which may be done with the engine or by
pushing it. While it may get the car out of the slippery spot if it is small, a 4WD
car is not likely to get stuck in a small slippery spot. In a swamp, for example,
it will take a great deal of rocking to get to the other side.
There are a number of useful methods that can be applied when stuck in snow
or mud for lack of traction. They are presented here in no particular order, and
should be selected in relation to the problem at hand.
A LIMITED SLIP DIFFERENTIAL may be aided in its work by lightly
pressing the brake pedal with the left foot while operating the accelerator with
the right foot. This will simulate traction for one of the wheels if both wheels
on an axle are spinning. Then the special differential will be able to do its job
of providing power to the wheel with better traction.
A SPINNING WHEEL on a car without a limited slip differential can often be
slowed by lightly pressing the brake pedal, as outlined above.
MOMENTUM may help get a car through a slick spot. If stuck, back up as far
as possible, then charge into the obstacle with as much speed as possible.
Momentum may get the car through; it should at least move it a few feet more
from where it had been. The process can then be repeated.
BRANCHES, brush, sand, boards, grass, rags, or anything else that might
increase traction can be put in front of the wheels if the car can back up a bit. This
improvement may be combined with the momentum method mentioned above
to get the car moving again.
THE JACK can be used to lift the wheels if the car cannot move backward or
forward. Raise a wheel and put in rocks, sticks, burlap, grass, branches, a truck
tarpaulin, or anything else that may increase traction. Let the wheel down with
the jack and repeat the process on the other wheels.
PATIENCE can be a virtue if the sun is shining on a car stuck in mud. Using a
shovel, remove mud from around the vehicle, and let the sun dry the area
sufficiently to allow the car to move. Often this may take some time, but the time
would otherwise be spent in hard physical labor trying to get the car out, and it
is much easier to wait for the sun to do the work.
MOVING WATER in a swampy area can also be used to carry mud away. It will
be necessary to channel the water, using a shovel, so that it will move the mud
from the area where the car is stuck. If the mud rests on a hard base it will
probably soak up the water and make more mud, worsening the problem.
THE PARKING BRAKE can often be used to hold a spinning wheel so that the
other wheel on that axle can be used to move the car. If the car has parking brakes
on each rear wheel rather than a single brake on the transmission, fasten a rope
to the wire cable that operates the brake on the spring wheel using a C-clamp
or locking pliers. Pass the rope under the chassis, under the front of the car, and
into the cab. Pull hard on the rope, possibly using a short lever such as a stick
of wood or hammer handle, and this will pull the wire cable, setting the brake
on one wheel. While holding the brake on, gently apply power. As the car begins
to move, release the parking brake extension rope and drive out of the difficult
area. (See Figure 4.01)
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If this method cannot be used, almost any means can be tried to stop a wheel from
spinning. Some suggestions include wedging the space between the spinning
wheel and the body with a big plank, chaining the wheel to the chassis so it
cannot turn, or jamming it with rocks under the fender. The other wheel on that
axle will then get the power that was wasted on spinning, possibly moving the
car. Of course, such wedging or other fastening must be removed as soon as the
car is free or the wheel will be dragged and may halt the car.
All of these expedients are made unnecessary on the Mercedes-Benz Unimog,
which has locks for both differentials. Both wheels on the axle lock together so
that if either one gets traction it will move the Unimog, and the other won't spin.
4.02 Hung Up in Mud or Snow
The second major threat from mud or snow is snow deep enough in it to allow
the chassis to become hung up. This creates so much drag on the car that the tires
lose traction, and the car cannot proceed.
This difficulty is often more easily dealt with than that of pure loss of traction,
since the driver is able to see the obstacle and can either remove it or go around
it. Perhaps the most common method of extricating a car from deep snow or mud
is to dig it out, thus removing the obstacle.
As outlined in Section 3.05, there are snow conditions in which it is unreasonable
to expect a car to operate without a plow. If snow is two feet (1/2 meter) or
less in depth, a 4WD car with chains should be able to get through.
If the front end is hung up in the snow or mud, try backing out. It may help to
add some traction under the wheels using sand, gravel, sticks, leaves, grass,
planks, or whatever else is at hand. Once off the obstacle, cut it down with
shovels and try again.
If a snow drift threatens to block forward progress, the driver can try pushing
ahead into the deep section, stopping before becoming hung up on the snow,
then backing out and trying again. A short distance will be gained each time until
the car breaks through the drift. Drivers who hit the drift at full speed generally
get hung up before breaking through.
Removing part of the load is another useful expedient. It allows the frame to rise
on the springs, since the springs are not so heavily loaded. This increase in
ground clearance may make it possible to get the car out. It should at least make
it easier to free the car. The axles may rise slightly as a result of reduced load
on the tires, but will not rise as much as the chassis.
If the car cannot be backed up, it will be necessary to lift it over the obstacle.
With a small car and a large number of people it may be possible to lift the car
enough by hand to get off the obstacle. Otherwise jack up the wheels one by one
and pack the space under them with logs, sticks, or planks. This will provide
a raised roadway, albeit rather crude, on which the car can be driven over the
trouble spot.
Once the car is moving again, use every means to keep it going. Momentum is
a great aid to getting a car through deep snow or mud, and keeping a car moving
slowly is much easier than getting it started from a dead stop. If the hazard is an
extensive one, it may be advisable to drive with one side of the car off the road,
up on the ridge of snow or mud, if the ridge is packed hard enough. Once moving,
Sections 3.04 and 3.05 will provide some assistance on how to keep the car
going.
4.03 Hung Up on a Solid Obstacle
Although similar to being hung up in mud or snow, the problem of getting stuck
on a rock, stump, or other solid obstacle presents its own difficulties. The prime
concern is to avoid damage to the car, since a rock can rip a hole in the crankcase
or gas tank or cause damage to the steering or drive train.
It is not usually practical to pull a solid obstacle out from under the car, since
the weight of the car is resting on it. If the car has a winch, it may be possible
using the technique described in Section 6.52. The only alternative is to lift the
car off the obstacle. The most common way of doing this is with a jack, lifting
the car and placing logs or planks under the wheels to raise the chassis off the
obstacle. It may only be necessary to raise one side of the car, particularly if the
obstacle is off center.
4.04 Log Bridges
Getting stuck in a log bridge can mean either the inconvenience of having to
extricate the car from between the logs or the major calamity of losing the car
into the water. Difficulties involving submerging are discussed in Section 5.01.
If the tires are stuck between the logs of a bridge, spinning will rarely get them
out. As explained in Section 4.01, the heat that results from the friction will only
damage the tires. Much greater tractive power results if the wheels do not spin.
Often it may be possible for several people to lift a car upward and forward while
it is driven off the bridge.
A jack can be used to lift the wheel from the space between the logs, and the car
can then be intentionally pushed sideways off the jack, dropping the wheel onto
a log. (See Figure 4.04a)
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A plank can be used to fill the space between logs. The tire should be jacked up
from the hole and the plank inserted under it to provide a temporary roadway.
The tire is then lowered onto the plank and the car driven off the bridge.
A small tree trunk or branch can be used as a ramp from below the bridge in some
cases. Insert one end of the log, perhaps four inches (10 cm) in diameter, in
between the separated logs in front of the stuck tire from the underside of the
bridge. Push it forward as far as it will go, and then raise the free end from the
river until it meets the tire. A rope can be used to haul the lower end of the log
upward and secure it temporarily while the car is driven off. (See Figure 4.04b)
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4.05 Fording
Being stuck while fording a stream is no different from being stuck elsewhere,
with one principal exception: if the car is stuck with the engine or tailpipe under
water, do not try to restart the engine once it has stopped. Pull the car out of the
water with other power: people, another car, animals, etc.
Otherwise, all the expedients listed elsewhere in this section apply to a car stuck
in water.
5.00 PROCEDURES WHEN STRANDED
In the event that none of the advice given in Sections 4.00 through 4.05 or any
other attempts will extricate the vehicle, then it may be considered stranded, and
additional assistance will be necessary. In this event one must either await the
arrival of help or go and look for assistance.
There are many parts of the world where being stranded is a serious matter, due
to intemperate weather, wild animals, lack of food or water, or simply the
remoteness of the area. This book is not intended as a survival course, but there
are several items to review in advance, before you find yourself stranded.
Because of the variety of supplies that may be needed in a vehicle used in a
remote area, a complete section (Section 14. 10)has been devoted to this subject.
LEAVING THE CAR is generally not a good idea unless you (or a member of
your party) are absolutely sure of where you are and where the nearest source
of help is, and how to get there. In hot areas such as deserts the car provides
shelter and shade, which are not available elsewhere. The best shelter in a desert
will be found by digging a hole under the car.
In very cold climates the vehicle will provide shelter from wind, and the bulk
of the car makes it more easily seen by potential rescuers than an individual
person walking alone.
In any climate the car will provide shelter from animals. Even if the car has
turned over, it is generally safer and more comfortable to sleep in it than on the
ground. A check should be made to see that no gas is leaking to cause a fire
hazard.
A WATER SUPPLY should be carried in the car in any area where drinking
water is not readily found.
In a warm climate, if no water is available, a simple solar still can be constructed.
Dig a hole about a foot deep and three feet in diameter and place a cup or other
container in the middle of it. Lay a sheet of clear plastic over the hole and weight
the edges with a ring of dirt to hold it in place. Into the center of the plastic drop
a small stone so that the plastic points downward into the cup. Water will
condense from the soil due to the heat of the sun, and will drop from the center
of the plastic sheet into the cup. (See Figure 5.00)
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In snow-covered areas, snow can be melted to provide drinking water. If there
is no wood Or Other local fuel, consider putting a small amount of gasoline on
a disposable air cleaner element and burning it. Snow can be contained in a
hubcap or a tool box for heating over the fire.
WALK FOR HELP only along the road, if there is one, unless a member of the
party is very familiar with the area. In general, even though the distance is
greater, it is better to follow the road when searching for assistance. This is
especially true if there are any other vehicles in the area that might use the same
road or a connecting road.
SIGNALS can be made to attract attention, either by day or night. If people are
known to be nearby, it may be possible to attract their attention by sounding the
car horn.
In the daytime, a smoky fire will usually be seen from a distance of many miles
on a calm day. Gasoline from the car can be used to start the fire. For fuel, either
sticks or a tire can be used. Once a good fire has been made with dry sticks, green
branches can be added to make smoke. If using a tire pick the worst one on the
car, take it off the rim, and arrange a good pile of kindling to get it started. A tire
is hard to ignite, and some rags soaked in gas or some other source of heat will
be needed to start it burning. Once started, the fire will produce a great deal of
thick black smoke.
At night, make a fire on high ground so that it can be seen.
5.01 Vehicle Submerged
If a car has become submerged in water it may be considered stranded, since the
engine cannot be used to extricate it. The principal consideration will be getting
all the occupants out and marking the location of the car. Then recovery
operations can be arranged.
GETTING OUT of a submerged car is no trouble if the doors have been
removed. If they have not, the water pressure will prevent them from being
opened until the car has nearly filled with water. For this reason it will be
necessary to escape through a window or wait until the car has nearly filled
before opening a door. In a tightly built car this may take as much as several
hours, although generally 10 or 15 minutes is a more average time.
LIFE PRESERVERS may be arranged for those who cannot swim if the car is
some distance from land. In many 4WD cars the seat cushions are made of foam
rubber, and will float. Empty or partially empty fuel cans are excellent floats,
and a spare tire will float even while carrying the weight of the steel rim.
MARKING THE LOCATION may be important if the car is likely to be moved
by current or will be hard to find for any other reason. Tie a rope or string to the
car and attach the other end to a float for a marker.
ANCHOR THE CAR if it is in fast-moving water where it may be carried off
by current. It can be tied with rope or cable to any secure anchor on the land such
as a tree.
SALVAGE OPERATIONS become quite routine in some areas where bridges
are not reliable, or where roads often follow waterways. In the Netherlands, for
example, emergency crews have been formed whose sole job is the recovery of
vehicles from canals.
A winch on a recovery vehicle can usually provide enough power to haul out a
submerged car. Winching techniques for salvage are described in Section 6.40.
If no winch is available, two or more vehicles may be needed to pull out the
submerged car. The towing cable should be attached to front towing hooks on
the submerged car, or to its front axle. If the car is not upright under the water,
it will be much easier to right the vehicle while most of the weight is supported
by the water rather than after it is on land. This can be done with cables to the
salvage vehicles.
When the car has been brought near land and starts to rise above the surface of
the water, it will be necessary to let any water drain out of it to lighten the load
on the recovery vehicles. Open any doors or other water-retaining barriers to
drain the car as completely as possible as it comes out of the water.
FLOATATION can be used when the submerged car cannot be dragged over a
rocky bottom for fear of damaging it. To float the car, it is necessary to put
containers of air inside the car, or attach them to the outside. The containers may
be old inner tubes, oil drums, gas cans, or even plastic bags filled with air. The
air displaces the heavier water, and raises the car to the surface.
An ordinary 55-gallon (200 liter) fuel drum will lift about 300 pounds (1 35 kg)
if the water is pumped out of it. To use a drum or any similar container, first fill
it with water so that it just barely floats, and arrange it in the submerged vehicle
so that the filling hole is at the bottom. An Enginair pump, tire pump, the exhaust
from the salvage vehicle (if the submerged car is not too deep), or any other
source of air can be used to pump air into the drum. The bubbles will rise inside
the drum, gradually moving the water out through the filling hole. When air
bubbles have filled the drum they will start to pour out the filling hole, rising to
the surface and indicating that the process is completed.
When enough containers have been put in or attached to the car and filled with
air in this manner, the car will rise to the surface and can then be pulled to shore
with a cable and recovered.
Section 7.10 on field expedients after submerging describes how to rehabilitate
the car.
6.00 WINCHES AND TOWING
So many recovery processes use a winch, or towing by another vehicle, that the
two have been grouped in this section. Suggestions for towing a trailer are also
included.
The basic tool for all of these operations is the tow rope, which may be a natural
or synthetic fiber rope or strap, wire cable, chain, or any combination of these.
6.01 Wire Rope
The most common form of tow cable or winch cable is wire rope. The basic
advantage of this material over fiber rope such as manila is its great strength. In
comparison to chain, wire rope offers lighter weight for the same strength. The
following table illustrates the breaking strength of several common sizes of
uncoated fiber core plow steel rope. (Galvanized cable is about 90 percent of this
strength.)
Nominal Diameter Breaking Strength
1/4 inch (6.25 mm) 5,660 pounds ( 2,570 kg)
5/16 inch (8 mm) 8,780 pounds ( 3,980 kg)
3/8 inch (9.5 mm) 12,300 pounds ( 5,580 kg)
7/16 inch (11 mm) 16,400 pounds ( 7,440 kg)
1/2 inch (12.5 mm) 21,100 pounds ( 9,570 kg)
9/16 inch (14.25 mm) 26,300 pounds (11,930 kg)
5/8 inch (16 mm) 32,400 pounds (14,700 kg)
3/4 inch (19 mm) 46,200 pounds (20,950 kg)
7/8 inch (22.25 mm) 62,800 pounds (28,490 kg)
1 inch (25.5 mm) 81,900 pounds (37,150 kg)
It is evident from examination of this chart that even with relatively small cable
the weight that can be supported will be in excess of the weight of the car. There
is, therefore, no advantage to using very heavy wire cable in most cases. It is very
difficult to work with, since it is hard to bend and join, and it is very heavy.
6.02 Joining Wire Cable
The greatest disadvantage of wire cable is the difficulty of joining one section
to another. With fiber rope, this is easily done with a knot, but if a wire rope
becomes knotted the strands will be kinked and weakened. Often a knot cannot
be removed from wire rope if it has been strained. Also, a knot will jam in a
winch mechanism and will keep the cable from lying flat.
The inability to use ordinary knots in wire rope need not be a handicap if the
cables are prepared in advance. Every piece of cable should have either a hook
or a loop in each end, never just a straight end.
HOOKS can be placed in wire rope for the greatest ease of attachment to another
length of cable or to a car or tree. Hooks are available with holes through which
the cable can be passed. The cable is then joined as described in succeeding
paragraphs.
EYES can be made in the end of wire rope by splicing, but this is a very difficult
and time consuming task. A much easier way is to use several U-bolts to secure
the eye.
An excellent compromise between the spliced eye, with its tremendous strength,
and an eye with U-bolts, which is very quick to make, is a folded eye. It is made
by unraveling the end of the wire rope into two strands approximately equal in
thickness. As the cable is unraveled it retains its form, leaving a channel where
the other half had been. Unravel the cable for about three feet, then fold the ends
around in opposite directions to form an eye. Carefully lay the strands back
together again to complete the eye, then clamp the remaining pigtail of cable
with a U-bolt or rope clip. (See Photo 6.02d.)
aom16.gif (600x600)
A hook can be placed in this type of eye by threading the two strands through
the hole in the hook from the opposite directions before rejoining the two halves.
Short sections of wire cable, perhaps 8 feet (2.5 meters) to 15 feet (4.5 meters)
in length, are much more valuable when traveling in convoy than a single great
length. They save handling unneeded cable and can be readily stored.
TO JOIN LOOPS in the ends of cables that have no hooks, put one loop through
the other, and then secure it with a heavy rod such as a tire iron, jack handle,
wrench or some other convenient item. A long as a strain is maintained on the
cable this joint will hold well. (See Figure 6.02.)
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KINKED WIRE CABLE that has been pulled tight will be much weaker than
the rest of the cable. Cut out the kinked section and make two shorter cables;
there is no practical way of salvaging a kinked section of cable.
This series of photographs <see photos 6.02a & 6.02b> depicts a simple way to make a strong eye in the end
aom14.gif (600x600)
of a wire cable, such as a winch cable or towing line. First, locking pliers are
placed on the cable to prevent it from unwinding too far. Then the cable is split
into two relatively equal portions and unwound back to the pliers. A shown in
Photo 6.02b, the portions of cable are then threaded through the eye of the hook,
if one is to be used.
In the top photograph, the two segments of the cable have been mated together
to form the eye. The remaining portion, above the pliers in Photo 6.02c, will be
aom15.gif (600x600)
mated to complete the re-forming of the cable. In photo 6.02d, U-clamps have
aom16.gif (600x600)
been installed and the end of the splice wrapped with tape to avoid injury from
the spiny wires. Notice that one of the U-clamps is mounted on the eye, and the
other two on the standing portion of the wire and the pigtail end. For light loads,
one U-bolt may be sufficient.
6.03 Storage of Wire Rope
aom18.gif (486x486)
Since wire rope is not very flexible, storage often becomes a problem. On some
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cars, the front bumper can be used for storage. On a Land-Rover or Toyota Land
Cruiser, for example, a great length of wire rope can be wound in a figure 8
aom49.gif (600x600)
around the ends of the front bumper.
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If cable is stored on the front bumper, be sure that it cannot hang down and get
snagged on a rock or some other obstacle. The cable is very strong, and could
do considerable damage to the car before the vehicle stopped or the obstacle was
torn away.
Wire rope can also carried conveniently by wrapping around a wheel trim. On
cars where space is provided for more than one spare tire, this may be a useful
way to carry cable. On a truck with flat sides, two wheels can be attached so that
wire rope can be wrapped around them in a figure 8. (See Figure 6.03)
On a Land-Rover, where the spare tire is carried on the hood, it is often
convenient to wind a short cable around the spare tire. If the cable is not often
needed in a Land-Rover station wagon, it can be wrapped around the backs of
the rear seats, between the seats and the wall.
It is often convenient to carry cable on the cab roof. A light basket can be made
from reinforcing rod to carry the cable, or a conventional cartop carrier may
serve the purpose.
6.10 Types of Fiber Rope
The two basic types of rope are fiber rope and wire rope. The fiber rope may
be subdivided into natural and synthetic fibers. Each offers distinct advantages
for certain jobs.
MANILA ROPE is the best of the natural fiber ropes. The individual strands
of fiber are long and strong, making a rope that has greater strength and
durability than hemp, jute, sisal, or other materials sometimes used for rope.
The following chart illustrates the maximum breaking strength of manila rope
as supplied by one manufacturer.
Rope Diameter Breaking Strength
1/2 inch (12.5 mm) 2,600 pounds (1,180 kg)
5/8 inch (16 mm) 4,400 pounds 2,000 kg)
3/4 inch (19 mm) 5,400 pounds (2,450 kg)
1 inch (25.5 mm) 9,000 pounds (4,080 kg)
1 1/4 inch (31 mm) 13,500 pounds (6,120 kg)
In actual service, a rope should not be stressed to more than half of the breaking
strength. If an emergency dictates that the rope must be stressed to near the
breaking strength, it should be retired from strenuous service because of the
danger that it may break with the next heavy pull. Similarly, any rope that has
been knotted and pulled severely so that the imprint of the knot remains in the
rope should be retired.
WHIPPING THE ENDS of a rope is the process of binding fibers so that they
do not fray at the ends. If the fibers do start to fray, the rope will soon unravel,
or come unwound. This makes it very difficult to tie the end of the rope, and
weakens it substantially since the pull is not equal on each strand.An easy way
to whip the ends of fiber rope is to wrap them in black plastic electrical tape. A
better way is to use a piece of light string as described in the following steps: (See
Figure 6.10.)
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1. Leave a few inches (cm) of string hanging over the end of the rope and lay
the string along the rope from the end back about two inches (5 cm). Hold
it with the thumb of the left hand while supporting the rope in the palm of
the hand.
2. Pull the main part of the string back beside the first strand, leaving a loop
that is held by the thumb of the left hand.
3. Starting about an inch (2.5 cm) from the end of the rope, begin winding the
string around the rope, spiraling toward the left thumb.
4. When the wrapping has nearly reached the loop, cut the string and pass the
end of the spiral through the loop.
5. Pull on the free end of the string that was left hanging in step 1. This will
draw the other end under the wrapping. When the end is about halfway into
the wrapping, cut off both ends of the string and trim the rope to complete
the job.
Braided rope, such as clothesline, can be prevented from fraying by dipping the
ends in varnish or lacquer.
SPLICING an eye into the end of the rope is not difficult, and makes a permanent
loop at the end for attaching the rope to a car, tree, or whatever is needed. While
splicing is not a hard job, it requires practice and is beyond the scope of this
book. One of the best ways to learn splicing is from a sailor or fisherman.
STORAGE of natural fiber ropes should be in a place where there is ventilation
to prevent rot from moisture. Natural fiber rope should be dried before storing
if it is damp or wet.
6.11 Synthetic Fiber Ropes
As a replacement for natural fiber ropes, synthetic fiber ropes have become very
popular, and can be used for the same purposes. They are strong and light and
resist rot. They can be used with a capstan winch, for towing, and other similar
purposes.
NYLON ROPE was one of the first successful synthetic fiber ropes. Nylon
makes a very strong rope with some stretch, which can take up the shock of
towing a disabled vehicle. The cost of nylon rope is higher than manila, but it
lasts longer and is less subject to abuse. In addition, it will float, and doesn't rot.
POLYPROPYLENE ROPE has recently become available in large sizes. It is
stronger than nylon or manila, and so light that it will float, but it does not have
as much stretch as nylon. The initial cost is about the same as manila. It is an
excellent all-purpose rope for towing, anchoring, winching, and other heavy
use. It is also available in small diameters for securing a load in a truck and
similar purposes. Even the very small diameters will hold 500 to 1,000 pounds
(225 to 450 kg).
WHIPPING THE ENDS of a synthetic rope is easily done with heat. Simply put
the end of the rope in a flame, or press it against a hot ember from a wood or coal
fire. The heat will fuse the fibers together.
SPLICING AN EYE in synthetic rope is just as useful as with natural fibers. The
only difference is that a longer splice is needed because the fibers are more
slippery than manila. Small diameters of synthetic rope are usually braided and
cannot be spliced by ordinary methods; an eye must be tied in the end.
6.12 Knots for Fiber Ropes
One of the great advantages of fiber rope over wire rope is that it can be easily
tied in knots. Probably the most useful knot for towing and winching is the
bowline. This is for several reasons: it cannot jam, and no matter how hard it is
stressed it can be easily opened; it will not slip up to make a smaller eye under
strain; it can be used to join a rope to another rope or to an object such as a car
or tree.
As with any knot, the only way to become familiar with it is through practice.
Take a small piece of rope and tie this knot over and over again until it becomes
second nature, and it loses its mystery.
To tie a bowline, follow the accompanying diagrams and remember the little
story that has helped novices learn this most useful knot for centuries: "Once
upon a time there was a snake who lived in a hole near a tree. One day the snake
awoke in his hole and decided to see what was going on outside. He stuck his
head out of the hole, went around the tree, and, seeing nothing that interested
him, went back down in his hole." The standing end of the rope is the tree; the
free end is the snake. (See Figure 6.12)
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SQUARE KNOTS should never be used to join two ropes for towing, since
pulling will jam them so tightly that they cannot be untied without damaging the
rope.
TO JOIN TWO ROPES for towing, tie a bowline in the end of one rope, then
tie an interlocking bowline in the other. In similar fashion, a bowline can be used
to join fiber rope to wire rope, chain, or some other object.
If a fiber rope is tied to a sharp-edged object, such as a spring shackle or car
bumper, it should be protected with a layer of rags, a piece of old tire, a piece
of hose or some other padding. If a rope is to be used for this type of service as
a regular thing, such as the end of a winch cable, it is preferable to attach a short
length of chain to the end of the rope, and a hook on the end of the chain. The
chain will make it possible to connect to any sharp-edged object without cutting.
TOWING with a fiber rope is more satisfactory than with wire rope or chain
because it can stretch. This same advantage, however, means that the load must
be applied gradually if the rope is not to be broken. This is not a serious problem
with a winch, where drum speed is very low, but it should be remembered when
towing a derelict or extricating a stuck vehicle.
6.13 Nylon Towing Straps <see photos 6.13a-6.13d>
aom210.gif (600x600)
Commercially prepared nylon towing straps are available, consisting of a strong
flat strap with forged steel hooks on each end. Generally about 20 feet (6 meters)
in length, these straps are very compact when folded up and several can be
carried in a small cloth bag. They are most useful for connecting a towing
vehicle to a stuck vehicle, rather than with a winch. These straps are relatively
inexpensive and are a worthwhile investment.
In contrast to a wire cable, the nylon towing strap has the ability to stretch. This
gives the nylon strap two great advantages: First, the potential for damage to
both the stuck and towing vehicles caused by the sudden exertion of a great deal
of force is virtually eliminated. Second, there is tremendous potential energy in
the stretched towing strap. The stuck vehicle thus has, in effect, two forces
working to remove it: the tractive effort of the towing truck, and the potential
energy stored in the stretched cable. This can double the pulling force on the
stuck vehicle, in comparison to the use of wire cable, which can only transfer
the tractive effort of the towing vehicle to the stuck vehicle.
Although the same effect is achieved if a nylon towing strap is used in
conjunction with a winch, the stretching value is not as great. The best use of the
towing strap is a direct connection between the chassis of the towing vehicle and
the chassis of the stuck vehicle. The towing vehicle should pull on the towing
strap until it is barely tight, then the towing car should make a maximum effort
to jerk the stuck vehicle free. The combined tractive force and extension of the
strap can be very effective. Several straps can be used for a longer reach by
connecting them to each other. The stretching effect is cumulative and is
therefore greatly increased by using two or three tow straps in series.
6.20 Chain
Chain offers greater ease of handling than wire rope, and greater strength than
fiber rope. It is easy to handle and does not get kinked or jammed easily. It can
be wrapped around an axle or bumper without damage, since the metal links will
not be cut by sharp edges.
The principal disadvantages of chain are its heavy weight and the difficulty of
joining one piece to another. It is also subject to rust.
6.21 Joining Chain
Since it is difficult or impossible to tie knots in chain, other methods must be
used to join pieces together. The most convenient is to have a hook at each end
of the chain.
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Hooks can be either the wide-mouth type, which will slip over
links, or the narrow-mouth type--sometimes called snatch hooks--which are
only wide enough to hold one link and will not slip over the next link. The snatch
hook is often easier to get unfastened after towing or winching, since the hook
does not slip under the car to the axle or other point of attachment.
Chain can be joined to a piece of wire rope to provide a tow cable of greater value
then either element used alone. The ends should be made of short pieces of
chain, perhaps three feet long, with a hook at the end. The main body of the tow
cable should be made of wire rope. It is not possible to use chain on a capstan
winch, since friction with the turning capstan would be insufficient to pull the
chain. While it would theoretically be possible to use chain on a drum winch,
the bulk would be much too great. The combination of chain and wire rope
overcomes these disadvantages. <see photos 6.021b-6.021c>
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6.22 Storage of Chain
Chain, since it is very flexible, is easier to store than wire rope. Since it cannot
rot, it avoids one of the big problems of natural fiber rope.
Chain can be carried in a cloth bag under the seat of a car, or in a tool box of the
type that many 4WD cars have under the front seat.
If a spare tire is carried on the hood such as is often done with the Land-Rover
chain can be carried in the depression at the center of the wheel. This should not
be done in areas where the car is likely to capsize, since the chain will be needed
after capsizing and may be under the car.
6.23 Repairs
The most satisfactory way to repair chain is by welding. A link is cut and spread
enough to admit the other end of the broken portion, then closed and welded.
Split links are also available at very little cost for chain repairs. These are similar
in appearance to regular links, except that they have been split lengthwise so that
they can be opened. (See Figure 6.23a)
aom24.gif (486x486)
A bolt can be used to connect the ends of a broken chain, but the end product will
not be as strong as a section of unbroken chain. (See Figure 6.23b)
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Probably the most common way of repairing chain is with a piece of wire passed
through the ends of the two parts as many times as is practical. While this may
serve as a field expedient, it should not be regarded as a permanent repair.
6.30 The Winch
The winch is probably the most useful single accessory item on a car used in
difficult terrain. Where a car must normally depend on the traction of its wheels,
the winch makes it possible to move the car without any traction whatever from
the wheels.
Virtually any 4WD vehicle can be fitted with a winch on the front end. Many
can also be provided with a winch at the rear for special purposes.
While a winch does represent a major investment, it should be remembered that
it can be transferred to another car at some later date when the present vehicle
is no longer useful.
6.31 Selecting a Winch
Many manufacturers offer only one model of which for a given vehicle. This
removes the necessity for making a choice. In cases where several types are
offered, the following points should be considered:
A WORM GEAR in the drive train of the winch will keep it from slipping
backward when power is removed. The worm gear is usually used to drive the
end of the drum on which the cable is wound. It consists of a threaded shaft
similar to a very large bolt, which is turned by the power source. The threads
engage teeth in a circular gear around the end of the cable drum. When the
threaded shaft turns, the gear teeth are slowly "screwed" around to turn the drum.
aom26.gif (486x486)
TWO BASIC TYPES of winch are in commo