Automotive Technology/Suspension and Steering

From Wikiversity
Jump to navigation Jump to search

This page is written for those taking the ASE A4 test

  • Always mark the placement of any part before removal

Steering[edit | edit source]

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[edit | edit source]

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[edit | edit source]

Also known as worm gears

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

Rack and Pinion Steering Gear[edit | edit source]

Other parts[edit | edit source]

Air bag Steering wheel Clock spring

Worm gear Idler arm Rack and pinion

Tie rods

Power Steering Units[edit | edit source]

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

Diagnosis[edit | edit source]

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[edit | edit source]

  • Inspect and adjust steering linkage geometry

Pitman arm[edit | edit source]

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[edit | edit source]

If bent, will affect front wheel toe

Idler arm[edit | edit source]

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

Remove and Replace

Suspension[edit | edit source]

Front Suspension[edit | edit source]

Rear Suspension[edit | edit source]

Alignment[edit | edit source]

Frame[edit | edit source]


Springs[edit | edit source]

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[edit | edit source]

MacPherson Struts
Short/Long Arm

ASE Task List[edit | edit source]

Glossary[edit | edit source]

Aspect ratio
The lip of the tire that seals the rim flange
Material under the tread
Center section AKA Spider
Center of a steel wheel
DOT tire code
E-metric tire
High flotation tire
Inner liner
Load index
Lug nuts
Major splice
Ply steer
Rim width
Speed rating
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