Thư viện tri thức trực tuyến
Kho tài liệu với 50,000+ tài liệu học thuật
© 2023 Siêu thị PDF - Kho tài liệu học thuật hàng đầu Việt Nam
Today’s technician : Classroom manuals for Automotive Suspension and Steering Systems
Nội dung xem thử
Mô tả chi tiết
Classroom Manual for
Automotive Suspension
& Steering Systems
Fifth Edition
This page intentionally left blank
Classroom Manual for
Automotive Suspension
& Steering Systems
Don Knowles
Fifth Edition
Australia • Canada • Mexico • Singapore • Spain • United Kingdom • United States
© 2011 Delmar, Cengage Learning
ALL RIGHTS RESERVED. No part of this work covered by the copyright herein
may be reproduced, transmitted, stored, or used in any form or by any means
graphic, electronic, or mechanical, including but not limited to photocopying,
recording, scanning, digitizing, taping, Web distribution, information networks,
or information storage and retrieval systems, except as permitted under
Section 107 or 108 of the 1976 United States Copyright Act, without the prior
written permission of the publisher.
Library of Congress Control Number: 2009904277
ISBN-13: 978-1-4354-8115-2
ISBN-10: 1-4354-8115-1
Delmar
5 Maxwell Drive
Clifton Park, NY 12065-2919
USA
Cengage Learning is a leading provider of customized learning solutions with
offi ce locations around the globe, including Singapore, the United Kingdom,
Australia, Mexico, Brazil and Japan. Locate your local offi ce at:
international.cengage.com/region
Cengage Learning products are represented in Canada by Nelson Education, Ltd.
For your lifelong learning solutions, visit delmar.cengage.com
Visit our corporate website at cengage.com.
Notice to the Reader
Publisher does not warrant or guarantee any of the products described herein or perform any independent analysis
in connection with any of the product information contained herein. Publisher does not assume, and expressly
disclaims, any obligation to obtain and include information other than that provided to it by the manufacturer. The
reader is expressly warned to consider and adopt all safety precautions that might be indicated by the activities
described herein and to avoid all potential hazards. By following the instructions contained herein, the reader willingly assumes all risks in connection with such instructions. The publisher makes no representations or warranties
of any kind, including but not limited to, the warranties of fi tness for particular purpose or merchantability, nor are
any such representations implied with respect to the material set forth herein, and the publisher takes no responsibility with respect to such material. The publisher shall not be liable for any special, consequential, or exemplary
damages resulting, in whole or part, from the readers’ use of, or reliance upon, this material.
Today’s Technician™: Suspension & Steering
Systems, 5th Edition
Don Knowles
Vice President, Career and Professional
Editorial: Dave Garza
Director of Learning Solutions: Sandy Clark
Executive Editor: David Boelio
Managing Editor: Larry Main
Senior Product Manager: Matthew Thouin
Editorial Assistant: Jillian Borden
Vice President, Career and Professional
Marketing: Jennifer McAvey
Executive Marketing Manager: Deborah S. Yarnell
Marketing Coordinator: Mark Pierro
Production Director: Wendy Troeger
Production Manager: Mark Bernard
Content Project Manager: Cheri Plasse
Art Director: Benj Gleeksman
For product information and technology assistance, contact us at
Professional Group Cengage Learning Customer & Sales Support, 1-800-354-9706
For permission to use material from this text or product,
submit all requests online at cengage.com/permissions.
Further permissions questions can be e-mailed to
Printed in the United States of America
1 2 3 4 5 X X 10 09 08
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii
Chapter 1 Suspension and Steering Systems. . . . . . . . . . . . . . . . . . . .1
• Introduction 1 • Frames and Unitized Bodies 2 • Front Suspension Systems 4
• Rear Suspension Systems 5 • Tires, Wheels, and Hubs 7 • Shock Absorbers and Struts 9
• Computer-Controlled Suspension Systems and Shock Absorbers 11 • Steering Systems 13
• Wheel Alignment 20 • Summary 25 • Terms to Know 25 • Review Questions 25
• Multiple Choice 26
Chapter 2 Basic Theories. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
• Introduction 28 • Newton’s Laws of Motion 28 • Work and Force 29 • Energy 29
• Energy Conversion 30 • Inertia 30 • Momentum 30 • Friction 31 • Mass, Weight, and Volume 31
• Torque 31 • Power 32 • Principles Involving Tires and Wheels in Motion 32
• Principles Involving the Balance of Wheels in Motion 34 • Principles Involving Liquids
and Gases 36 • Atmospheric Pressure 39 • Vacuum 40 • Venturi Principle 42
• Summary 42 • Terms to Know 42 • Review Questions 43 • Multiple Choice 43
Chapter 3 Wheel Bearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
• Introduction 45 • Bearing Loads 46 • Ball Bearings 46 • Roller Bearings 48 • Seals 50
• Wheel Bearings 51 • Rear-Axle Bearings 55 • Bearing Lubrication 56 • Summary 57
• Terms to Know 57 • Review Questions 57 • Multiple Choice 58
Chapter 4 Tires and Wheels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
• Introduction 60 • Tire Design 61 • Tire Ply and Belt Design 63 • Tire Tread Design 64
• Tire Manufacturing Defects 64 • Tire Ratings and Sidewall Information 65 • Specialty Tires 68
• Replacement Tires 69 • Tire Valves 70 • Tire Chains 72 • Compact Spare Tires 72
• Run-Flat Tires 73 • Tire Pressure Monitoring Systems 75 • Tire Contact Area 79
• Tire Placard and Infl ation Pressure 80 • Tire Motion Forces 81 • Wheel Rims 82
• Static Wheel Balance Th eory 84 • Dynamic Wheel Balance Th eory 86 • Noise, Vibration,
Harshness 87 • Terms to Know 91 • Summary 91 • Review Questions 92 • Multiple Choice 93
Chapter 5 Shock Absorbers and Struts . . . . . . . . . . . . . . . . . . . . . . . .95
• Introduction 95 • Shock Absorber Design 95 • Shock Absorber Operation 96 • Gas-Filled Shock
Absorbers and Struts 98 • Heavy-Duty Shock Absorber Design 99 • Shock Absorber Ratios 100
• Strut Design, Front Suspension 100 • Shock Absorber and Strut Design, Rear Suspension 101
• Travel-Sensitive Strut 103 • Adjustable Struts 103 • Load-Leveling Shock Absorbers 104
• Electronically Controlled Shock Absorbers and Struts 105 • Summary 107 • Terms to Know 107
• Review Questions 107 • Multiple Choice 108
Chapter 6 Front Suspension Systems . . . . . . . . . . . . . . . . . . . . . . . .110
• Introduction 110 • Suspension System Components 111 • Short-and-Long Arm Front Suspension
Systems 120 • MacPherson Strut Front Suspension System Design 125 • Modifi ed MacPherson Strut
Suspension 130 • High-Performance Front Suspension Systems 130 • Torsion Bar Suspension 134
• Curb Riding Height 138 • Front Spring Sag, Curb Riding Height, and Caster Angle 138
• Spring Sag, Curb Riding Height, and Camber Angle 140 • Summary 141 • Terms to Know 141
• Review Questions 141 • Multiple Choice 142
Contents
v
vi
Chapter 7 Rear Suspension Systems . . . . . . . . . . . . . . . . . . . . . . . . .144
• Introduction 144 • Live-Axle Rear Suspension Systems 144 • Semi-Independent Rear Suspension
Systems 150 • Independent Rear Suspension Systems 151 • Curb Riding Height 162
• Spring Sag, Curb Riding Height, and Caster Angle 163 • Summary 163 • Terms to Know 163
• Review Questions 164 • Multiple Choice 164
Chapter 8 Computer- Controlled Suspension Systems. . . . . . . . . . .166
• Introduction 167 • Programmed Ride Control System 167 • Electronic Air Suspension System
Components 171 • Electronic Air Suspension System Operation 181 • Air Suspension System
Design Variations 183 • Vehicle Dynamic Suspension System 184 • Electronic Suspension
Control (ESC) System 185 • Integrated Electronic Systems and Networks 193 • Vehicle Stability
Control 197 • Active Roll Control Systems 203 • Adaptive Cruise Control (ACC) Systems 205
• Lane Departure Warning (LDW) Systems 205 • Collision Mitigation Systems 206 • Telematics 206
• Summary 208 • Terms to Know 208 • Review Questions 209 • Multiple Choice 210
Chapter 9 Steering Columns and Steering Linkage
Mechanisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
• Introduction 212 • Conventional Nontilt Steering Column 214 • Tilt Steering Column 217
• Electronic Tilt/Telescoping Steering Column 219 • Active Steering Column 220 • Driver Protection
Module 221 • Steering Linkage Mechanisms 222 • Steering Damper 229 • Summary 230
• Terms to Know 230 • Review Questions 230 • Multiple Choice 231
Chapter 10 Power Steering Pumps . . . . . . . . . . . . . . . . . . . . . . . . . .233
• Introduction 233 • Power Steering Pump Drive Belts 234 • Types of Power-Assisted Steering
Systems 235 • Power Steering Pump Design 238 • Power Steering Pump Operation 240
• Hybrid Vehicles and Power Steering Systems 241 • Hybrid Powertrain Components 242
• Various Types of HEVs 248 • Fuel Cell Vehicles 249 • Summary 250 • Terms to Know 250
• Review Questions 251 • Multiple Choice 252
Chapter 11 Recirculating Ball Steering Gears. . . . . . . . . . . . . . . . . .253
• Introduction 253 • Manual Recirculating Ball Steering Gears 254 • Power Recirculating Ball
Steering Gears 256 • Summary 260 • Terms to Know 260 • Review Questions 260
• Multiple Choice 261
Chapter 12 Rack and Pinion Steering Gears . . . . . . . . . . . . . . . . . . .263
• Introduction 263 • Manual Rack and Pinion Steering Gear Main Components 264 • Steering Gear
Ratio 265 • Manual Rack and Pinion Steering Gear Mounting 265 • Advantages and Disadvantages
of Rack and Pinion Steering 265 • Power Rack and Pinion Steering Gears 266 • Types of Power
Rack and Pinion Steering Gears 270 • Electronic Variable Orifi ce Steering 273 • Saginaw Electronic
Variable Orifi ce Steering 275 • Rack-Drive Electronic Power Steering 277 • Electronic Power
Steering System Operation 279 • Column-Drive Electronic Power Steering 287 • Column-Drive
Electronic Power Steering Operation 289 • Pinion-Drive Electronic Power Steering 289
• Active Steering Systems 290 • Active Steering System Components 292 • Active Steering
Operation 294 • Power Steering System 294 • Steer-by-Wire Systems 296 • Summary 297
• Terms to Know 297 • Review Questions 298 • Multiple Choice 299
Contents
vii
Chapter 13 Four-Wheel Steering Systems. . . . . . . . . . . . . . . . . . . . .301
• Introduction 301 • Electronically Controlled Four-Wheel Steering 302
• Input Sensors 304 • Four-Wheel Steering System Operation 304 • Quadrasteer Four-Wheel
Steering Systems 305 • Quadrasteer Four-Wheel Steering System Operation 312
• Rear Active Steering System 313 • Four-Wheel Active Steering (4WAS) 315
• Summary 318 • Terms to Know 318 • Review Questions 319 • Multiple Choice 320
Chapter 14 Frames and Frame Damage . . . . . . . . . . . . . . . . . . . . . .321
• Introduction 321 • Types of Frames and Frame Construction 322 • Unitized Body Design 324
• Vehicle Directional Stability 325 • Vehicle Tracking 326 • Types of Frame Damage 327
• Summary 330 • Terms to Know 330 • Review Questions 331 • Multiple Choice 331
Chapter 15 Four Wheel Alignment, Part 1 . . . . . . . . . . . . . . . . . . . . .333
• Introduction 333 • Wheel Alignment Th eory 334 • Importance of Four Wheel
Alignment 334 • Rear Wheel Alignment and Vehicle Tracking Problems 335 • Types of Wheel
Alignment 337 • Computer Alignment Systems 339 • Camber Fundamentals 345
• Driving Conditions Aff ecting Camber 346 • Caster Fundamentals 348 • Safety Factors
and Caster 352 • Steering Terminology 352 • Summary 353 • Terms to Know 353
• Review Questions 354 • Multiple Choice 355
Chapter 16 Four Wheel Alignment, Part 2 . . . . . . . . . . . . . . . . . . . . .357
• Introduction 357 • Steering Axis Inclination (SAI) Defi nition 358 • SAI Purpose 359
• SAI and Safety Factors 359 • Scrub Radius 360 • Wheel Setback 361 • Toe Defi nition 362
• Toe Setting for Front-Wheel-Drive and Rear-Wheel-Drive Vehicles 362 • Toe Adjustment
and Tire Wear 362 • Turning Radius 363 • Rear Wheel Alignment 365 • Summary 367
• Terms to Know 368 • Review Questions 368 • Multiple Choice 369
Glossary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .371
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .389
Contents
viii
Th anks to the support the Today’s Technician series has received from those who teach
automotive technology, Delmar Cengage Learning, the leader in automotive-related
textbooks, is able to live up to its promise to regularly provide new editions of texts of this
series. We have listened and responded to our critics and our fans and present this new
updated and revised fi fth edition. By revising this series on a regular basis, we can respond to
changes in the industry, changes in technology, changes in the certifi cation process, and to the
ever-changing needs of those who teach automotive technology.
We also listened to instructors who said something was missing or incomplete in the last
edition. We responded to those and the results are included in this fi fth edition.
Th e Today’s Technician series features textbooks that cover all mechanical and electrical
systems of automobiles and light trucks. Principally, the individual titles correspond to the
certifi cation areas for 2009 in areas of National Institute for Automotive Service Excellence
(ASE) certifi cation.
Additional titles include remedial skills and theories common to all of the certifi cation areas
and advanced or specifi c subject areas that refl ect the latest technological trends.
Th is new edition, like the last, was designed to give students a chance to develop the same
skills and gain the same knowledge that today’s successful technician has. Th is edition also
refl ects the changes in the guidelines established by the National Automotive Technicians
Education Foundation (NATEF) in 2008.
Th e purpose of NATEF is to evaluate technician training programs against standards
developed by the automotive industry and recommend qualifying programs for certifi cation
(accreditation) by ASE. Programs can earn ASE certifi cation upon the recommendation
of NATEF. NATEF’s national standards refl ect the skills that students must master. ASE
certifi cation through NATEF evaluation ensures that certifi ed training programs meet or
exceed industry-recognized, uniform standards of excellence.
Th e technician of today and for the future must know the underlying theory of all automotive
systems and be able to service and maintain those systems. Dividing the material into two
volumes, a Classroom Manual and a Shop Manual, provides the reader with the information
needed to begin a successful career as an automotive technician without interrupting the
learning process by mixing cognitive and performance learning objectives into one volume.
Th e design of Delmar’s Today’s Technician series was based on features that are known to
promote improved student learning. Th e design was further enhanced by a careful study of
survey results, in which the respondents were asked to value particular features. Some of
these features can be found in other textbooks, while others are unique to this series.
Each Classroom Manual contains the principles of operation for each system and subsystem.
Th e Classroom Manual also contains discussions on design variations of key components
used by the diff erent vehicle manufacturers. It also looks into emerging technologies that will
be standard or optional features in the near future. Th is volume is organized to build upon
basic facts and theories. Th e primary objective of this volume is to allow the reader to gain an
understanding of how each system and subsystem operates. Th is understanding is necessary
to diagnose the complex automobiles of today and tomorrow. Although the basics contained
in the Classroom Manual provide the knowledge needed for diagnostics, diagnostic
procedures appear only in the Shop Manual. An understanding of the underlying theories is
also a requirement for competence in the skill areas covered in the Shop Manual.
Preface
ix
Preface
A coil-ring-bound Shop Manual covers the “how-to’s.” Th is volume includes step-by-step
instructions for diagnostic and repair procedures. Photo Sequences are used to illustrate
some of the common service procedures. Other common procedures are listed and are
accompanied with fi ne line drawings and photos that allow the reader to visualize and
conceptualize the fi nest details of the procedure. Th is volume also contains the reasons for
performing the procedures, as well as when that particular service is appropriate.
Th e two volumes are designed to be used together and are arranged in corresponding
chapters. Not only are the chapters in the volumes linked together, the contents of the
chapters are also linked. Th is linking of content is evidenced by marginal callouts that refer
the reader to the chapter and page that the same topic is addressed in the other volume. Th is
feature is valuable to instructors. Without this feature, users of other two-volume textbooks
must search the index or table of contents to locate supporting information in the other
volume. Th is is not only cumbersome but also creates additional work for an instructor
when planning the presentation of material and when making reading assignments. It is also
valuable to the students; with the page references, they also know exactly where to look for
supportive information.
Both volumes contain clear and thoughtfully selected illustrations. Many of which are original
drawings or photos specially prepared for inclusion in this series. Th is means that the art is a
vital part of each textbook and not merely inserted to increase the number of illustrations.
Th e page layout, used in the series, is designed to include information that would otherwise
break up the fl ow of information presented to the reader. Th e main body of the text includes
all of the “need-to-know” information and illustrations. In the wide side margins of each page
are many of the special features of the series. Items that are truly “nice-to-know” information
such as: simple examples of concepts just introduced in the text, explanations or defi nitions
of terms that are not defi ned in the text, examples of common trade jargon used to describe a
part or operation, and exceptions to the norm explained in the text. Th is type of information
is placed in the margin, out of the normal fl ow of information. Many textbooks attempt to
include this type of information and insert it in the main body of text; this tends to interrupt
the thought process and cannot be pedagogically justifi ed. By placing this information off to
the side of the main text, the reader can select when to refer to it.
Jack Erjavec
Series Editor
Highlights of this Edition—Classroom Manual
Th e text was updated to include the latest technology in suspension and steering systems.
Some of these systems include hybrid vehicle steering systems, active steering systems, rear
active steering (RAS), four-wheel active steering (4WAS) systems, data network systems,
computer-controlled suspension systems, and adaptive cruise control systems. Th e text also
includes the latest technology in vehicle stability control systems, traction control systems,
active roll control, lane departure warning (LDW) systems, collision mitigation systems,
telematics, and tire pressure monitoring systems (TPMS).
Th e fi rst chapter explains the design and purpose of basic suspension and steering systems.
Th is chapter provides students with the necessary basic understanding of suspension and
steering systems. Th e other chapters in the book allow the student to build upon his or her
understanding of these basic systems.
x
Preface
Th e second chapter explains all the basic theories required to understand the latest suspension
and steering systems described in the other chapters. Students must understand these basic
theories to comprehend the complex systems explained later in the text.
Th e other chapters in the book explain all the current model systems and components such
as wheel bearings, tires and wheels, shock absorbers and struts, front and rear suspension
systems, computer-controlled suspension systems, steering columns and linkages, power
steering pumps, steering gears and systems, four-wheel steering systems, frames, and fourwheel alignment. Many art pieces have been replaced or updated throughout the text to
improve visual concepts of suspension and steering systems and components.
Highlights of this Edition—Shop Manual
Th e chapters in the Shop Manual have been updated to explain the diagnostic and service
procedures for the latest systems and components described in the Classroom Manual.
Diagnostics is a very important part of an automotive technician’s job. Th erefore, proper
diagnostic procedures are emphasized in the Shop Manual.
A number of new Photo Sequences have been added in Chapters 3 through 16. Th ese
Photo Sequences illustrate the correct diagnostic or service procedure for a specifi c system
or component. Th ese Photo Sequences allow the students to visualize the diagnostic or
service procedure. Visualization of these diagnostic and service procedures helps students to
remember the procedures, and perform them more accurately and effi ciently. Th e text covers
the information required to pass a ASE test in Suspension and Steering Systems.
Chapter 1 explains the necessary safety precautions and procedures in an automotive repair
shop. General shop safety and the required shop safety equipment are explained in the text.
Th e text describes safety procedures when operating vehicles and various types of automotive
service equipment. Correct procedures for handling hazardous waste materials are detailed in
the text.
Chapter 2 describes suspension and steering diagnostic and service equipment and the use
of service manuals. Th is chapter also explains employer and employee obligations and ASE
certifi cation requirements.
Th e other chapters in the text have been updated to explain the diagnostic and service
procedures for the latest suspension and steering systems explained in the Classroom Manual.
Some new job sheets related to the new systems and components have been added in the
text. Many art pieces have been replaced or updated to improve the student’s visualization of
diagnostic and service procedures.
Don Knowles
xi
Features of the Classroom Manual include
the following:
Classroom Manual
COGNITIVE OBJECTIVES
These objectives defi ne the contents of the
chapter and defi ne what the student should
have learned upon completion of the chapter.
Each topic is divided into small units to
promote easier understanding and learning.
CROSS-REFERENCES
TO THE SHOP MANUAL
Reference to the appropriate
page in the Shop Manual is given
whenever necessary. Although the
chapters of the two manuals are
synchronized, material covered in
other chapters of the Shop Manual
may be fundamental to the topic
discussed in the Classroom Manual.
MARGINAL NOTES
These notes add “nice-toknow” information to the
discussion. They may include
examples or exceptions, or
may give the common trade
jargon for a component. 3
The unitized body provides a steel box around the passenger compartment to provide
passenger protection in a collision. In most unitized bodies, special steel panels are inserted in
the doors to protect the vehicle occupants in a side collision. Some unitized body components
are manufactured from high-strength or ultra high-strength steels. The unitized body design
is typically used in small- and mid-sized front-wheel-drive cars. A steel cradle is mounted
under the front of the unitized body to support the engine and transaxle (Figure 1-3). Rubber
and steel mounts support the engine and transaxle on the cradle. Large rubber bushings are
mounted between the cradle and the unitized body to help prevent engine vibration from
reaching the passenger compartment. Some unitized bodies have a partial frame mounted
under the rear of the vehicle to provide additional strength and facilitate the attachment of
rear suspension components (Figure 1-4).
Vehicle weight plays a significant role in fuel consumption. One automotive design
engineer states that “Fuel economy improvements are almost linear with weight reduction.
A 30 percent reduction in vehicle weight provides approximately a 30 percent improvement
in fuel economy.” If a Toyota Prius weighs 3,300 lb (1,497 kg) and provides 50 miles per gallon
(mpg), the same Prius would provide 55 mpg if it weighed 3,000 lb (1,360 kg).
Carbon dioxide (CO2
) emissions are a major concern for automotive manufacturers,
because CO2
is a greenhouse gas that contributes to global warming. Vehicle manufacturers
are facing increasingly stringent CO2
emission standards. CO2
emissions are proportional
to fuel consumption. Reduced fuel consumption results in lower CO2
emissions. Therefore,
reducing vehicle weight results in less fuel consumption and lower CO2
emissions. Reduced
weight also contributes to improved vehicle performance.
Shop Manual
Chapter 14, page 472
Carbon dioxide
is a byproduct of
the gasoline, diesel
fuel, or ethanol
combustion process.
A greenhouse gas
is one that collects
high in the earth’s
atmosphere and
covers the earth
like a blanket, due
to which more heat
is retained on the
planet.
In the United States,
it is estimated that
automobiles contribute 1.5 billion tons
of CO2
to the atmosphere each year.
Coal-burning power
plants produce 2.5
billion tons of CO2
each year.
E
D
B
a A
b
e
d
Left side Right side
TOP
SIDE
FIGURE 1-3 Engine cradle. FIGURE 1-4 Rear partial frame.
1
Suspension
and Steering
Systems
Chapter 1
O The difference between a shock absorber and a strut.
O Two different types of computer-controlled shock
absorbers.
O The advantages of computer-controlled suspension
systems.
O Two types of steering linkages.
O How the rack is moved in a rack and pinion steering
gear.
O How a power steering pump develops hydraulic
pressure.
O The advantages of four-wheel steering.
O The result of incorrect rear wheel toe.
O Front wheel caster.
O The results of excessive negative camber.
Upon completion and review of this chapter, you should be able
to understand and describe:
O How strength and rigidity are designed into a
unitized body.
O The advantages of reduced vehicle weight.
O The design of a short-and-long arm (SLA) front
suspension system.
O How limited independent rear wheel movement is
provided in a semi-independent rear suspension
system.
O The advantage of an independent rear suspension
system.
O The purposes of vehicle tires.
O The terms positive and negative offset as they relate
to vehicle wheel rims.
O Three different loads that are applied to wheel
bearings.
O The purposes of shock absorbers.
Introduction
The suspension system must provide proper steering control and ride quality. Performing
these functions is extremely important to maintain vehicle safety and customer satisfaction. For example, if the suspension system allows excessive vertical wheel oscillations, the
driver may lose control of the steering when driving on an irregular road surface. This loss of
steering control can result in a vehicle collision and personal injury. Excessive vertical wheel
oscillations transfer undesirable vibrations from the wheel(s) to the passenger compartment,
which causes customer dissatisfaction with the ride quality.
The suspension system and frame must also position the wheels and tires properly to
provide normal tire life and proper steering control. If the suspension system does not position each wheel and tire properly, wheel alignment angles are incorrect and usually cause
excessive tire tread wear. Improper wheel and tire position can also cause the steering to
pull to one side. When the suspension system positions the wheels and tires properly, the
steering should remain in the straight-ahead position if the car is driven straight ahead on a
98
valves and orifices to provide enough friction to prevent the spring from overextending on
the rebound stroke. These piston valves and orifices must not create excessive friction, which
slows the wheel from returning to its original position.
Shock absorber pistons have many different types of valves and orifices. In some pistons,
small orifices control the oil flow during slow wheel and suspension movements. Stacked steel
valves control the oil flow during medium speed wheel and suspension movements. During
maximum wheel and suspension movements, larger orifices between the piston valves provide oil flow control. On other shock absorber pistons, the stacked steel valves alone provide
oil flow control. Regardless of the piston orifice and valve design, the shock absorber must be
precisely matched to absorb the spring’s energy.
During fast upward wheel movement on the compression stroke, excessive pressure in
the lower oil chamber forces the base valve open and thus allows oil to flow through this valve
to the reservoir. The nitrogen gas provides a compensating space for the oil that is displaced
into the reservoir on the compression stroke and when the oil is heated. Since the gas exerts
pressure on the oil, cavitation, or foaming of the oil, is eliminated. When oil bubbles are
eliminated in this way, the shock absorber provides continuous damping for wheel deflections as small as 0.078 in (2.0 mm). A rebound rubber is located on top of the piston. If the
wheel drops downward into a hole, the shock absorber may become fully extended. Under
this condition, the rebound rubber provides a cushioning action.
Gas-Filled Shock Absorbers and Struts
Gas-filled units are identified with a warning label. If a gas-filled shock absorber is removed
and compressed to its shortest length, it should re-extend when it is released. Failure to reextend indicates that shock absorber or strut replacement is necessary.
WARNING: New gas-filled shock absorbers are wired in the compressed position for shipping purposes. Exercise caution when cutting this wire strap
because shock absorber extension may cause personal injury. After the upper
shock absorber attaching bolt is installed, the wire strap can be cut to allow the
unit to extend. Front gas-filled struts have an internal catch that holds them in
the compressed position. This catch is released when the strut rod is held and
the strut rotated 45° counterclockwise.
WARNING: Do not throw gas-filled shock absorbers or struts in the fire or apply
excessive heat or flame to these units. These procedures may cause the unit to
explode, resulting in personal injury.
WARNING: Never apply heat to a shock absorber or strut chamber with an
acetylene torch. This action may cause a shock absorber or strut explosion
resulting in personal injury.
Shop Manual
Chapter 5,
page 173
A gas-filled shock
absorber contains a
nitrogen gas charge
to maintain pressure
on the oil in the
shock.
Author’s Note: Of all the suspension components, shock absorbers and struts
contribute the most to ride quality. As the vehicle is driven over road irregularities,
the shock absorbers or struts are continually operating to control the spring action
and provide acceptable ride quality. It has been my experience that shock absorbers
and struts usually wear out first in suspension systems, because they are working
every time a wheel strikes a road irregularity. Therefore, you must understand not
only shock absorber and strut operation but also how ride quality is affected if these
components are not functioning properly. Thus, you must know shock absorber and
strut diagnosis and service procedures.
CAUTION:
When drilling wornout shock absorbers
or struts to relieve
the gas pressure
prior to disposal,
drill the shock
absorber only
at the vehicle
manufacturer’s
specified location.
CAUTIONS AND
WARNINGS
Throughout the text, warnings
are given to alert the reader
to potentially hazardous
materials or unsafe conditions.
Cautions are given to advise
the student of things that can
go wrong if instructions are not
followed or if a nonacceptable
part or tool is used.
xii
A BIT OF HISTORY
This feature gives the student
a sense of the evolution of
the automobile. This feature
not only contains nice-toknow information, but also
should spark some interest
in the subject matter.
REVIEW QUESTIONS
Short answer essay, fi ll-in-the-blank, and
multiple-choice questions are found at the
end of each chapter. These questions are
designed to accurately assess the student’s
competence in the stated objectives
at the beginning of the chapter.
AUTHOR’S NOTES
This feature includes simple
explanations, stories, or
examples of complex topics.
These are included to
help students understand
diffi cult concepts.
TERMS TO
KNOW LIST
A list of new terms
appears next to
the Summary.
SUMMARIES
Each chapter concludes with
a summary of key points
from the chapter. These are
designed to help the reader
review the chapter contents.
24
Wheel Setback
Wheel setback occurs when one wheel is driven rearward in relation to the opposite front
wheel (Figure 1-39). Setback may occur on rear wheels, but is most likely to be present on
front wheels. Setback is usually caused by collision damage.
Positive scrub
radius
Negative
scrub radius
Vertical
reference
FIGURE 1-38 Scrub radius.
FIGURE 1-39 Setback.
Setback
A BIT OF
HISTORY
China is one of the
emerging automotive markets in
the world. In 2002
Chinese car sales
totaled 1,126,000.
This was the first
year that car sales
in China exceeded
1,000,000, and car
sales from 2001
to 2002 increased
approximately 50%.
Total sales of cars,
trucks, and buses
totaled 3,500,00
in 2002. In the first
3 months of 2003
car sales increased
40% to 1,360,000.
Experts predict that
car sales in China
may never achieve
this rate of growth
again, but predict a
significant, steady
growth rate for the
Chinese automotive
industry. Some North
American vehicle and
parts manufacturers are forming
partnerships with
Chinese automotive
manufacturers and
building automotive
manufacturing
facilities in China.
Wheel setback
occurs when one
wheel is driven rearward in relation to
the opposite wheel.
e
.
2
in China exceeded
1,000,000, and car
sales from 2001
to 2002 increased
approximately 50%.
Total
p
e
p
C
m
bu
m
fac
147
During hard acceleration, the entire power train twists in the opposite direction to engine
crankshaft and drive shaft rotation. The engine and transmission mounts absorb this torque.
However, the twisting action of the drive shaft and differential pinion shaft tends to lift the
rear wheel on the passenger’s side of the vehicle. Extremely hard acceleration may cause the
rear wheel on the passenger’s side to lift off the road surface. Once this rear wheel slips on
the road surface, engine torque is reduced, and the leaf spring forces the wheel downward.
When this rear tire contacts the road surface, engine torque increases and the cycle repeats.
This repeated lifting of the differential housing is called axle tramp, and this action occurs on
live-axle rear suspension systems. Axle tramp is more noticeable on live-axle leaf-spring rear
suspension systems in which the springs have to absorb all the differential torque. For this
reason, only engines with moderate horsepower were used with this type of rear suspension.
Rear suspension and axle components such as spring mounts, shock absorbers, and wheel
bearings may be damaged by axle tramp. Mounting one rear shock absorber in front of the
rear axle and the other rear shock behind the rear axle helps reduce axle tramp.
Torque arm
Differential
Insulator
Track bar
FIGURE 7-6 Rear suspension system with long torque arm and track bar.
In some cars with higher torque engines, a long torque arm is bolted to the rear axle
housing (Figure 7-6). This torque arm helps prevent differential rotation during hard acceleration and braking. The front of this torque arm is mounted in a rubber insulator and bracket
that is bolted to the back of the transmission housing. This long torque arm helps prevent
Author’s Note: Leaf-spring rear suspension systems are still used on many lightduty trucks because of their load-carrying capability. However, today’s design engineers have improved the ride quality of these suspension systems compared with past
models. Ride quality in these leaf-spring suspension systems has been improved by
installing longer leaf springs and using larger, improved rubber insulating bushings
in the spring eye and shackle. Ride quality has also been improved by maximizing
the shock absorber mounting location and matching the shock absorber design more
closely to the leaf-spring jounce and rebound action. Optimizing the rear axle mounting position on the leaf springs also improves ride quality.
147
Torque arm
ear suspension system with long torque arm and track bar.
25
Terms to
Know
Angular bearing load
Carbon dioxide (CO2
)
Green house gas
Included angle
Jounce travel
Negative camber
Negative caster
Negative offset
Negative-phase steering
Positive camber
Positive caster
Positive offset
Positive-phase steering
Radial bearing load
Rebound travel
Scrub radius
Serpentine belt
Setback
Sideslip
Steering axis inclination
(SAI)
Thrust bearing load
Thrust line
Toe-out
Turning circle
Wheel alignment
Wheel offset
Wheel shimmy
Review Questions
Short Answer Essays
1. Explain how the engine and transaxle are supported
in a front-wheel-drive vehicle with a unitized body.
2. Explain the purpose of coil springs in a short-andlong arm front suspension system.
3. Describe how the top of the steering knuckle is
supported in a MacPherson strut front suspension
system.
4. Explain the disadvantages of a live axle rear
suspension system.
5. Explain the sources of CO2
related to gasoline production and vehicle operation.
6. Describe the design of a wheel rim with positive offset.
7. Explain a radial bearing load.
8. Describe jounce wheel travel.
O The suspension system must provide proper steering control and ride quality.
O The steering system must maintain vehicle safety and reduce driver fatigue.
O All parts of a unitized body are load-carrying members and these parts are welded
together to form a strong assembly.
O Carbon dioxide (CO2
) is a by-product of the gasoline, diesel fuel, or ethanol combustion
process.
O Greenhouse gasses collect in the earth’s upper atmosphere and form a blanket around the
earth, which traps heat nearer the earth’s surface.
O Front and rear suspension systems must provide proper wheel position, steering control,
ride quality, and tire life.
O A short-and-long arm (SLA) front suspension system has a lower control arm that is
longer than the upper control arm.
O In a MacPherson strut front suspension system, the top of the steering knuckle is
supported by the lower end of the strut.
O Rear suspension systems can be live axle, semi-independent, or independent.
O Wheel rims are manufactured from steel, cast aluminum, forged aluminum,
pressure-cast chrome-plated aluminum, or magnesium alloy.
O Wheel hubs contain the wheel bearings and support the load supplied by the vehicle
weight.
O Bearing loads can be radial, thrust, or angular.
O Shock absorbers control spring action and wheel oscillations.
O Computer-controlled suspension systems can contain air springs and/or computer-
controlled shock absorbers.
O The steering column connects the steering wheel to the steering gear.
O The steering linkage connects the steering gear to the front wheels.
O Steering gears can be recirculating ball or rack-and-pinion type.
O Proper wheel alignment provides steering control, ride quality, and normal tire tread
life.
O Improper wheel alignment contributes to steering pull when driving straight ahead,
improper steering wheel return, harsh ride quality, rapid tire tread wear, and steering pull
while braking.
Summary
xiii
To stress the importance of safe work habits, the Shop Manual also dedicates one full chapter to safety. Other
important features of this manual include:
BASIC TOOLS LISTS
Each chapter begins with
a list of the basic tools
needed to perform the tasks
included in the chapter.
MARGINAL NOTES
These notes add “nice-toknow” information to the
discussion. They may include
examples or exceptions, or
may give the common trade
jargon for a component.
SPECIAL TOOLS
LISTS
Whenever a special tool is
required to complete a task,
it is listed in the margin
next to the procedure.
387
Rack and Pinion
Steering Gear
Diagnosis
and Service
Chapter 12
O Diagnose oil leaks in power rack and pinion steering
gears.
O Disassemble, inspect, and repair power rack and
pinion steering gears.
O Adjust power rack and pinion steering gears.
O Diagnose Magnasteer.
O Diagnose electronic power steering systems.
Upon completion and review of this chapter, you should be able to:
O Perform a manual or power rack and pinion
steering gear inspection.
O Remove and replace manual or power rack and
pinion steering gears.
O Disassemble, inspect, repair, and reassemble
manual rack and pinion steering gears.
O Adjust manual rack and pinion steering gears.
O Diagnose manual rack and pinion steering systems.
Proper rack and pinion steering gear operation is essential to maintain vehicle safety and reduce
driver fatigue. Such steering gear conditions as looseness and excessive steering effort may contribute to a loss of steering control, resulting in a vehicle collision. Worn steering gear mountings
may cause improper wheel alignment and bump steer. Improper wheel alignment increases tire
tread wear, and bump steer may increase driver fatigue. Excessive steering gear looseness or high
steering effort also contribute to driver fatigue. Therefore, in the interest of vehicle safety and
driver alertness, rack and pinion steering gear diagnosis and service are extremely important.
Manual or Power Rack and Pinion Steering Gear On-Car
Inspection
The wear points are reduced to four in a rack and pinion steering gear. These wear points are
the inner and outer tie-rod ends on both sides of the rack and pinion assembly (Figure 12-1).
The first step in manual or power rack and pinion steering gear diagnosis is a very thorough
inspection of the complete steering system. During this inspection, all steering system components such as the inner and outer tie-rod ends, bellows boots, mounting bushings, couplings
or universal joints, ball joints, tires, and steering wheel free play must be checked.
Follow these steps for manual or power rack and pinion steering gear inspection:
1. With the front wheels straight ahead and the engine stopped, rock the steering wheel
gently back and forth with light finger pressure (Figure 12-2). Measure the maximum
steering wheel free play. The maximum specified steering wheel free play on some vehicles is 1.18 in. (30 mm). Always refer to the vehicle manufacturer’s specifications in the
service manual. Excessive steering wheel free play indicates worn steering components.
Bump steer occurs
when one of the
front wheels strikes
a road irregularity
while driving
straight ahead, and
the steering suddenly veers to the
right or left.
BASIC TOOLS
Basic technician’s
tool set
Service manual
Floor jack
Safety stands
Machinist’s rule
Shop Manual
PHOTO
SEQUENCES
Many procedures are
illustrated in detailed
Photo Sequences. These
detailed photographs
show the students
what to expect when
they perform particular
procedures. They
also can provide the
student a familiarity
with a system or type of
equipment, which the
school may not have.
PERFORMANCEBASED OBJECTIVES
These objectives defi ne the contents of
the chapter and defi ne what the student
should have learned upon completion of the
chapter. These objectives also correspond
with the list of required tasks for NATEF
certifi cation. Each NATEF task is addressed.
Although this textbook is not designed to
simply prepare someone for the certifi cation
exams, it is organized around the NATEF
task list. These tasks are defi ned generically
when the procedure is commonly followed
and specifi cally when the
procedure is unique for
specifi c vehicle models.
Imported and domestic
model automobiles and
light trucks are included
in the procedures. 38
g g gg g
may cause improper wheel alignment and bump steer. Improper wheel alignment increases tire
tread wear, and bump steer may increase driver fatigue. Excessive steering gear looseness or high
steering effort also contribute to driver fati Therefore, in the interest of vehicle saf nd
d i
Bump steer occu
when one of the
front wheels strik
a road irregularity
while driving
straight ahead, an
the steering suddenly veers to the
right or left.
BASIC TOOLS
Basic technician’s
tool set
Service manual
Floor jack
Safety stands
Machinist’s rule
ned generically
monly followed
136
Sensor Learning Procedure with Magnetic Tool
If a TPMS sensor or component is serviced, a sensor learning procedure must be performed.
There are a number of different sensor learning procedures depending on the vehicle make
and model year. The sensor learning procedure usually involves the use of a magnetic tool or
a scan tool.
Follow these steps to complete the sensor learning procedure with a magnetic tool:
1. Starting with the ignition switch off, cycle the ignition switch on and off three times, and
on the third cycle leave the ignition switch in the on position. Do not wait more than two
seconds between switch cycles.
2. Press and release the brake pedal.
3. Repeat the ignition switch cycling procedure as explained in step 1. Upon completion
of this procedure, the horn should sound once to indicate successful entry to the learn
mode.
4. After the horn sounds, a TRAIN LEFT FRONT TIRE message should appear in the
instrument panel message center.
5. Place the special magnetic tool on the valve stem of the left front tire (Figure 4-18). When
the TPMS module recognizes the left front sensor, the horn sounds momentarily.
WARNING: The special magnetic tool may adversely affect magnetically sensitive devices such as heart pacers, and this action may result in personal
injury!
6. Repeat step 5 at the right front, right rear, left rear, and spare wheels.
7. If the learn procedure fails on any wheel, the horn sounds twice, and a TIRES NOT
LEARNED-REPEAT message appears in the message center. If this action occurs, the
learn procedure must be repeated from step 1.
270°
FIGURE 4-17 Proper tire and wheel position on a tire changer.
SPECIAL TOOLS
Magnetic learn tool
jargon
P
S
M
i
P
d
s
w
t
p
a
s
w
e
s
Sensor Learning Procedure with Magnetic Tool
If a TPMS sensor or component is serviced, a sensor learning procedure must be performed.
There are a number of different sensor learning procedures depending on the vehicle make
and model year. The sensor learning procedure usually involves the use of a magnetic tool or
a scan tool.
Follow these steps to complete the sensor learning procedure with a magnetic tool:
1. Starting with the ignition switch off, cycle the ignition switch on and off three times, and
on the third cycle leave the ignition switch in the on position. Do not wait more than two
seconds between switch cycles.
2. Press and release the brake pedal.
3. Repeat the ignition switch cycling procedure as explained in step 1. Upon completion
of this procedure, the horn should sound once to indicate successful entry to the learn
mode.
4. After the horn sounds, a TRAIN LEFT FRONT TIRE message should appear in the
instrument panel message center.
5. Place the special magnetic tool on the valve stem of the left front tire (Figure 4-18). When
the TPMS module recognizes the left front sensor, the horn sounds momentarily.
WARNING: The special magnetic tool may adversely affect magnetically sensitive devices such as heart pacers, and this action may result in personal
injury!
6. Repeat step 5 at the right front, right rear, left rear, and spare wheels.
7. If the learn procedure fails on any wheel, the horn sounds twice, and a TIRES NOT
LEARNED-REPEAT message appears in the message center. If this action occurs, the
learn procedure must be repeated from step 1.
OOLS
tool
18
Typical Procedure for Removing Air Bag Module
P1-1 Tools required to remove the air
bag module: safety glasses, seat covers,
screwdriver set, torx driver set, battery
terminal pullers, battery pliers, assorted
wrenches, ratchet and socket set,
and service manual.
P1-2 Place the seat and fender covers
on the vehicle.
P1-3 Place the front wheels in the
straight-ahead position, and turn the
ignition switch to the LOCK position.
PHOTO SEQUENCE 1
P1-4 Disconnect the negative
battery cable.
P1-5 Tape the cable terminal to prevent
accidental connection with the battery
post. Note: A piece of rubber hose can be
substituted for the tape.
P1-6 Remove the SIR fuse from the fuse
box. Wait 10 minutes to allow the reserve
energy to dissipate.
P1-7 Remove the connector position
assurance (CPA) from the yellow
connector at the base of the
electrical
steering column.
P1-8 Disconnect the yellow two-way
electrical connector.
P1-9 Remove the four bolts that
secure the module from the rear of the
steering wheel.
xiv
CUSTOMER CARE
This feature highlights those
little things a technician
can do or say to enhance
customer relations.
JOB SHEETS
Located at the end of each
chapter, the Job Sheets provide
a format for students to perform
procedures covered in the chapter.
A reference to the NATEF Task
addressed by the procedure is
referenced on the Job Sheet.
49
Coil Spring Compressor Tool
WARNING: There is a tremendous amount of energy in a compressed coil
spring. Never disconnect any suspension component that will suddenly release
this tension because this may result in serious personal injury and vehicle or
property damage.
Many types of coil spring compressor tools are available to the automotive service industry
(Figure 2-17). These tools compress the coil spring and hold it in the compressed position
while removing the strut from the coil spring or performing other suspension work. Each type
of front suspension system requires a different type of spring compressor tool. The vehicle
manufacturer’s and equipment manufacturer’s recommended procedure must be followed.
Power Steering Pressure Gauge
WARNING: The power steering pump delivers extremely high pressure during
the pump pressure test. Always follow the recommended test procedure in the
vehicle manufacturer’s service manual to avoid personal injury during this test.
A power steering pressure gauge is used to test the power steering pump pressure
(Figure 2-18). Because the power steering pump delivers extremely high pressure during
this test, the recommended procedure in the vehicle manufacturer’s service manual must be
followed.
Strut
Jack
screw
Jack screw
nut
FIGURE 2-17 MacPherson strut coil spring compressor tool.
FIGURE 2-18 Power steering pressure gauge.
CAUTION:
The vehicle
manufacturer’s and
equipment manufacturer’s recommended procedures
must be followed for
each type of spring
compressor tool.
CAUTIONS AND WARNINGS
Throughout the text, warnings are given
to alert the reader to potentially hazardous
materials or unsafe conditions. Cautions are
given to advise the student of things that
can go wrong if instructions are not followed
or if a nonacceptable part or tool is used.
CROSSREFERENCES
TO THE
CLASSROOM
MANUAL
Reference to the
appropriate page in the
Classroom Manual is given
whenever necessary.
Although the chapters
of the two manuals are
synchronized, material
covered in other chapters
of the Classroom Manual
may be fundamental
to the topic discussed
in the Shop Manual.
Many types of coil spring compressor tools are available to the automotive service industry
(Figure 2-17). These tools compress the coil spring and hold it in the compressed position
while removing the strut from the coil spring or performing other suspension work. Each type
of front suspension system requires a different type of spring compressor tool. The vehicle
wed.
ring
the
est.
ure
ng
be
must be fo
each type
compresso
tool is used.
300
If the vehicle is not equipped with an air bag, the steering wheel removal and replacement
procedure is basically the same, but all steps pertaining to the air bag module and clock spring
are not required. On a non-air-bag–equipped vehicle, the center steering wheel cover must
be removed to access the steering wheel retaining nut. SERVICE TIP:
When servicing air
bag components on
some recent model
vehicles, the vehicle
manufacturer recommends disconnecting
the air bag components only in the zone
or area on the vehicle
where service work is
required rather than
disconnecting the
negative battery cable.
Classroom
Manual
Chapter 9,
page 214
CAUTION:
Do not hammer on
the top of the steering shaft to remove
the steering wheel.
This action may
damage the shaft.
Customer Care: While servicing a vehicle, always inspect the operation of the
indicator lights or gauges in the instrument panel. These lights or gauges may
indicate a problem that the customer has been ignoring. For example, if the air bag
warning light is not operating properly, the air bag or bags may not deploy in a collision, resulting in serious injury to the driver and/or passenger. If the air bag warning
light is not working properly, always advise the customer that he or she will not be
protected by the air bag in a collision, and the vehicle should not be driven under this
condition.
Steering Column Service
Some steering column service can be performed with the column installed in the vehicle. In
some steering columns removal and replacement of the various switches in the column is
possible with the column installed in the vehicle. Always follow the recommended service
procedure in the vehicle manufacturer’s service manual.
Steering Column Removal and Replacement
Steering column removal and replacement procedures vary depending on the vehicle make,
type of steering column, and gearshift lever position. Always follow the vehicle manufacturer’s recommended procedure in the service manual.
The following is a typical steering column removal and replacement procedure:
1. Disconnect the negative battery cable. If the vehicle is equipped with an air bag, wait one
minute.
2. Install a seat cover on the front seat.
3. Place the front wheels in the straight-ahead position and remove the ignition key from
the switch to lock the steering column.
4. Remove the cover under the steering column and remove the lower finish panel if
necessary.
5. Disconnect all wiring connectors from the steering column.
6. If the vehicle has a column-mounted gearshift lever, disconnect the gearshift linkage at
the lower end of the steering column. If the vehicle has a floor-mount gearshift, disconnect the shift interlock.
7. Remove the retaining bolt or bolts in the lower universal joint or flexible coupling.
8. Remove the steering-column-to-instrument-panel mounting bolts.
9. Carefully remove the steering column from the vehicle. Be careful not to damage the
upholstery or paint.
10. Install the steering column under the instrument panel and insert the steering shaft into
the lower universal joint.
11. Install the steering-column-to-instrument-panel mounting bolts. Be sure the steering
column is properly positioned, and tighten these bolts to the specified torque.
12. Install the retaining bolt or bolts in the lower universal joint or flexible coupling, and
tighten the bolts to the specified torque.
13. Connect the gearshift linkage if the vehicle has a column-mounted gearshift.
14. Connect all the wiring harness connectors to the steering column connectors.
300
CAUT
Do not hammer on
the top of the steering shaft to remove
the steering wheel.
This action may
damage the shaft.
11. Install the steering
column is properly positioned, and tighten these bo
12. Install the retaining bolt or bolts in the lower universal joint or flexible coupling,
tighten the bolts to the specified torque.
13. Connect the gearshift linkage if the vehicle has a column-mounted gearshift.
14. Connect all the wiring harness connectors to the steering column connectors.
159
Name ____________________________________ Date ______________________
Tire Dismounting and Mounting
Upon completion of this job sheet, you should be able to demount and mount tires.
NATEF Correlation
This job sheet is related to the NATEF Suspension and Steering Task F-6: Dismount,
inspect, and remount tire on wheel: Balance wheel and tire assembly (static and dynamic).
Tools and Materials
Tire changer Tire-and-wheel assembly
Procedure
1. Remove the valve core to release all the air pressure from the tire. Chalk mark the tire
at the valve stem opening in the wheel so the tire may be re-installed in the same position to maintain proper wheel balance.
Is all the air pressure released from the tire? Ȼ Yes Ȼ No
Is the tire chalk marked at the valve stem location in the wheel?
Instructor check __________________________________________________________
2. Guide the operating lever on the tire changer to unseat both tire beads. Are both tire
beads unseated? Yes ____________ No ____________
3. Place the tire-and-wheel assembly properly on the tire changer. Is the tire-andwheel assembly positioned properly on the tire changer? Yes ____________ No
____________
WARNING: Do not proceed to dismount the tire unless the tire-and-wheel
assembly is securely attached to the tire changer. This action may cause personal
injury.
4. Press the pedal on the tire changer that clamps the wheel to the changer. Is the wheel
clamped properly to the tire changer? Yes ____________ No ____________
5. Lower the arm on the tire changer into position on the tire-and-wheel assembly. Is
the tire changer arm positioned properly on the tire-and-wheel assembly?
Yes ____________ No ____________
6. Insert the tire iron properly between the upper tire bead and the wheel. Be sure the
tire iron is properly positioned. Depress the tire changer pedal that causes the wheel to
rotate. This rotation moves the top bead out over the wheel. Is the top tire bead above
the wheel rim? Yes ____________ No ____________
JOB SHEET 10
SERVICE TIP:
The following is a
generic tire demounting and mounting
procedure.
SERVICE TIPS
Whenever a short-cut
or special procedure is
appropriate, it is described in
the text. These tips are
generally those things
commonly done by
experienced technicians.