Leaf Spring System
Air Suspension
Shocks and Components
Suspension Terms
Inspection and diagnosis
100

This suspension component consists of several curved steel leaves stacked together to support vehicle weight.

Leaf Spring

100

This flexible rubber component uses compressed air to support the vehicle's weight.

Air spring/ Air bag

100

This suspension component helps control spring movement and reduces excessive vehicle bouncing.

Shock absorber

100

This term describes the repeated up-and-down movement of the suspension after it has been disturbed.

Oscillation

100

Before working underneath a raised heavy-duty vehicle, a technician should support it with properly rated equipment such as these.

Safety stands / Jack stands

200

The individual steel pieces that make up a leaf spring assembly are commonly held together to form this

Spring Pack

200

This valve controls air entering and exhausting from the air springs to maintain the proper vehicle ride height.

Leveling valve/ Height control valve

200

The compression movement of a suspension is known by this term.

Jounce

200

These components limit suspension travel and help prevent metal-to-metal contact when the suspension is fully compressed.

Jounce blocks / bump stops

200

Cracks, broken leaves, loose U-bolts, damaged bushings, and shifted spring components are items checked during an inspection of this type of suspension.

Leaf spring suspension

300

These U-shaped fasteners secure a leaf spring assembly to the axle.

U-Bolts

300

If this component is adjusted incorrectly, the vehicle may ride too high or too low even when there are no air leaks.

Leveling valve/ height control valve

300

The downward or extension movement of a suspension following compression is known as this.

Rebound

300

This suspension design uses a bar that twists to provide spring action.

Torsion bar suspension

300

Uneven ride height, damaged air springs, loose mounting hardware, and air leaks should be checked when inspecting this system.

Air spring suspension system

400

This component allows the effective length of a leaf spring to change as the suspension moves through jounce and rebound.

Spring Shackle

400

A truck is leaning toward one side after sitting overnight. This is one of the first problems a technician should look for in the air suspension.

Air leak

400

A shock absorber covered with excessive oil and unable to control suspension movement may require this service.

Replacement of Shock absorber

400

This heavy-duty suspension design commonly uses a beam to connect or distribute loads between axles.

Equalizing beam suspension

400

A truck has excessive body movement, poor ride control, and abnormal tire wear. These components should be inspected for worn bushings, leakage, or damage.

Shock absorbers and suspension components

500

During inspection, a technician finds a cracked leaf in a spring pack. The appropriate action is generally this rather than attempting to weld the damaged spring.

replace the damaged spring/spring assembly according to manufacturer procedures?

500

What is the best way to find an air leak?

Spray with soapy water

500

A truck continues bouncing several times after hitting a bump. These suspension components should be inspected closely.

Shock absorbers

500

This term refers to a suspension system capable of changing its characteristics or ride height in response to vehicle operating conditions.

Adaptive suspension

500

A truck's rear suspension sits lower than specification. The air springs are not leaking and system air pressure is adequate. This component should be checked next for adjustment or improper operation.

Leveling valve / height control valve