Automotive Technology/Suspension and Steering

This page is written for those taking the ASE A4 test

• Always mark the placement of any part before removal

Steering

Always disable the Air Bag system before any change to the steering column.

Steering Columns should be locked into place to preserve timing and prevent overextending the clock-spring.

Replace Bushings when they no longer hold the part in position. Replace Bearings when they have any visible play, or have a turning torque outside of specification.

Adjustments can affect front wheel toe

Diagnosis

Bump steer can be caused by

• Loose idler arm
• Loose rack mountings
• Loose or damaged mounting

Steering wheel free play can be caused by

• Worn couplings
• worn u joint
• Loose mounting

Steering problems are sometimes subframe alignment problems

Manual Steering Gears

Also known as worm gears

Noises, binding, looseness, hard steering point to bearing and lubrication problems.

Other parts

Air bag Steering wheel Clock spring

Worm gear Idler arm Rack and pinion

Tie rods

Power Steering Units

Power steering uses hydraulic pressure to apply force to the worm gear or rack

Diagnosis

Weeping, or a slight fluid leak requires repair or replacement

• inspect power steering fluid
• Remove and replace power steering pump belt, tensioner, pulley
• diagnose power steering pump problems
• Remove and replace power steering pump
• power steering pressure test
• Remove and replace power steering hydraulics
• Steering gear worm bearing preload and sector lash

• Remove and replace steering gear seals and gaskets

• Remove and replace rack and pinion unit
• Remove and replace rack and pinion steering gear bellows/boots.
• flush, fill, bleed power steering hydraulics
• Diagnose, Remove and replace variable-assist steering systems

Rack and Pinion Steering

can provide assistance by applying pressure to one side

Steering Linkage

• Inspect and adjust steering linkage geometry

Pitman arm

Pitman arm is only bent in collisions, and wears on other parts. These are pressed on, and are difficult to separate from the splines.

Center link

If bent, will affect front wheel toe

Idler arm

• Remove and Replace tie rods
• Remove and Replace steering linkage damper

Remove and Replace

Suspension

Frame

Frame

Springs

You should understand spring frequency, even if you never measure the frequency of the spring. Most spring are made of a chrome-vanadium alloy. Very tough stuff.

Leaf spring

Coil spring

Torsion bars

Constant-velocity joint

Usable in torque transfer

Suspension

Kingpin

MacPherson Struts

Short/Long Arm

Glossary

Aspect ratio

Bead

The lip of the tire that seals the rim flange

Belt

Material under the tread

Center section AKA Spider

Center of a steel wheel

Conicity

DOT tire code

E-metric tire

High flotation tire

Inner liner

Load index

Lug nuts

Major splice

Offset

Ply steer

Rim width

Run-flat

Sidewall

Speed rating

TPC

Tread

Unsprung Weight

Weight below the spring in a vehicle

Uniform Tire Quality Grading System (UTQG)

Tires sold in the USA are rated in Tread wear, Traction, and Temperature Resistance as per NHTSA.

Wear bars

raised features located at the bottom of the tread grooves that indicate the tire has reached its wear limit

Automotive Diagnostics