8/9/2019 67 to 70 Suspension-Steering FundamentalsI
1/53
Goodheart-Willcox Co., Inc.
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
2/53
Goodheart-Willcox Co., Inc.
Supports the weight of the vehicle
Allows the wheels to move up anddown
Allows rapid cornering without extreme
body roll Keeps the tires in firm contact with the
road
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
3/53
Goodheart-Willcox Co., Inc.
Functions of a
Suspension System Prevents excessive body squat when
accelerating or heavily loaded
Prevents excessive body dive whenbraking
Allows the front wheels to turn left orright for steering
Helps keep the wheels in correctalignment
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
4/53
Goodheart-Willcox Co., Inc.
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
5/53
Goodheart-Willcox Co., Inc.
Suspensions
Independent
Nonindependent
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
6/53
Goodheart-Willcox Co., Inc.
Types of Springs
A. Coil spring
B. Leaf spring
C. Air spring
D. Torsion bar
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
7/53
Goodheart-Willcox Co., Inc.
Coil Springs
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
8/53
Goodheart-Willcox Co., Inc.
Leaf Spring Assembly
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
9/53
Goodheart-Willcox Co., Inc.
Air Springs
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
10/53
Goodheart-Willcox Co., Inc.
Torsion Bar
The bar resists twisting action and acts
like a conventional spring
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
11/53
Goodheart-Willcox Co., Inc.
Control Arm Assembly
Control arm bushings act as bearings
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
12/53
Goodheart-Willcox Co., Inc.
Ball Joints
Tapered stud provides a force fit into the
steering knuckle or bearing support
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
13/53
Goodheart-Willcox Co., Inc.
Shock Absorber
Action
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
14/53
Goodheart-Willcox Co., Inc.
Gas-Charged Shock
Absorbers Use a low-pressure gas to help keep
the oil in the shock from foaming
Nitrogen gas is enclosed in a chamber
separate from the main oil cylinder
Gas pressure acting on the oil prevents
air bubbles from forming
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
15/53
Goodheart-Willcox Co., Inc.
Checking Shock
AbsorberCondition Perform a visual inspection for
damage, rubber bushing wear or oil
leakage
Perform a shock absorber bounce test
push down on one corner of the vehicle
release the body count the number of times the body
rebounds
maximum two or three oscillations
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
16/53
Goodheart-Willcox Co., Inc.
Sway Bar(Stabilizer Bar)
Sway bar links connect the bar
to the control arms
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
17/53
Goodheart-Willcox Co., Inc.
Front Suspension
(MacPherson Strut)
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
18/53
Goodheart-Willcox Co., Inc.
Strut Compressor
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
19/53
Goodheart-Willcox Co., Inc.
Twin I-Beam
Suspension
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
20/53
Goodheart-Willcox Co., Inc.
Nonindependent Rear
Suspension
Solid axle housing for rear-wheel-drive
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
21/53
Goodheart-Willcox Co., Inc.
Dead Axle
Solid axle that does not drive wheels
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
22/53
Goodheart-Willcox Co., Inc.
Independent Rear
Suspension
This differential is mounted to the frame
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
23/53
Goodheart-Willcox Co., Inc.
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
24/53
Goodheart-Willcox Co., Inc.
Provide precise control of the wheel
direction
Maintain correct steering effort
Transmit road feel to the drivers hands
Absorb most of the road shock going to
the steering wheel
Allow for suspension action
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
25/53
Goodheart-Willcox Co., Inc.
Two basic kinds of steering systems
are in use today:
Parallelogram steering systems
rack-and-pinion steering systems
Each may be operated manually or with
power assist
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
26/53
Goodheart-Willcox Co., Inc.
SteeringParallelogram
Steering
Basic Rack-and-
Pinion Steering
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
27/53
Goodheart-Willcox Co., Inc.
27
Parallelogram SteeringSystem
Fig. 2-5
Credit: ATW Assembly & Test Worldwide
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
28/53
Goodheart-Willcox Co., Inc.
28
Rack-and-Pinion SteeringSystem
Fig. 2-7
Credit: ATW Assembly & Test Worldwide
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
29/53
Goodheart-Willcox Co., Inc.
Steering
Gears
Rack-and-PinionGear
(rack and pinion steering)
Worm Steering Gear
(parallelogram steering)
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
30/53
Goodheart-Willcox Co., Inc.
Steering Rack
(Rack and Pinion Steering)
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
31/53
Goodheart-Willcox Co., Inc.
Steering Gear box
(parallelogram steering)
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
32/53
Goodheart-Willcox Co., Inc.
Power Steering
Systems Most systems use an engine-driven
pump and a hydraulic system to assist
steering action
An electric motorin the rack may be
used to provide assist
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
33/53
Goodheart-Willcox Co., Inc.
Basic Power Steering
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
34/53
Goodheart-Willcox Co., Inc.
Steering Wheel Play
Amount that you can turn the steering
wheel without front wheel movement
Caused by worn ball sockets, a wornidler arm, or too much clearance in the
steering gearbox
Compare the play to service manualspecifications
e.g. 1 1/2 (33 mm)
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
35/53
Goodheart-Willcox Co., Inc.
Dry Park Test
With the vehicle on the ground, rotate the
steering wheel back and forth while
someone watches for part wear
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
36/53
Goodheart-Willcox Co., Inc.
Steering Inspection
Raise the vehicle on a lift. Wiggle the
tires back and forth while watching
for steering play
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
37/53
Goodheart-Willcox Co., Inc.
Hard Steering Caused by problems with the steering
gear, power steering components, ballsockets, and the suspension system
Check the power steering pump belt forcondition and tension
If the belt is slipping, hard steering
could result Check for cracks and glazing and
compare tension to specs
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
38/53
Goodheart-Willcox Co., Inc.
Steering System Noise Noise can be a sign of worn parts, dry
bearings or ball sockets, loose parts,slipping belts, or low power steering
fluid level Belt squeal and power steering pump
noise both occur when the steeringwheel is turned
Pump noise can result from low fluidlevel or aerated fluid
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
39/53
Goodheart-Willcox Co., Inc.
Maintenance involves checking for lowfluid level, incorrect belt adjustment,
system leaks, and other problems
Ball socket lubrication may benecessary
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
40/53
Goodheart-Willcox Co., Inc.
Checking the Fluid
Check most systems at operating
temperature, with the engine off
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
41/53
Goodheart-Willcox Co., Inc.
Tire Problem
Under-inflated Tire
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
42/53
Goodheart-Willcox Co., Inc.
Tire Problem
Over-inflated Tire
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
43/53
Goodheart-Willcox Co., Inc.
Tire Problem
Cupping
Out of balance
Lack of properrotation
Broken belts in tire
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
44/53
Goodheart-Willcox Co., Inc.
Tire Problem
Alignment Problem
Worn Parts
Bent Parts
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
45/53
Goodheart-Willcox Co., Inc.
Alignment
Three Angles to check
Camber Caster
Toe
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
46/53
Goodheart-Willcox Co., Inc.
Camber
Positive camber
Tire leans away
from vehicle
Negative camber Tire leans
towards vehicle
Causes tire wear Causes vehicle
pulling
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
47/53
Goodheart-Willcox Co., Inc.
47
Camber
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
48/53
Goodheart-Willcox Co., Inc.
Caster Amount of upper
and lower ball
joint offset
Will causevehicle pull
Does not cause
tire wear
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
49/53
Goodheart-Willcox Co., Inc.
49
Caster
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
50/53
Goodheart-Willcox Co., Inc.
Toe
measurement
difference across
front and back of tires
Will cause tire wear
Will result in pulling or
wandering
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
51/53
Goodheart-Willcox Co., Inc.
51
Toe Angle
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
52/53
Goodheart-Willcox Co., Inc.
Tire Future
Tweel
Pneumatic tire
Michelin Experimented with
in Military and Off
Road applications
8/9/2019 67 to 70 Suspension-Steering FundamentalsI
53/53
Tire Future