1. Suspension System
Fundamentals

2. Functions of a Suspension System Supports the weight of the vehicle
Allows the wheels to move up and down
Allows cornering without extreme body roll
Keeps the tires in firm contact with the road
Allows the front wheels to turn left or right for steering
Suspension Components Video

3. Two Types of Suspension Systems
Independent
Nonindependent

4. Independent Suspension
Allows one wheel to move up and down with minimal effect on the other wheels
Each wheel is attached to its own suspension unit
Front Suspension Inspection Video

5. Springs
Springs compress and extend as a vehicle travels over bumps and holes in the road surface
Springs must support the weight of the vehicle while still allowing suspension travel (movement)

6. Coil Spring
A length of spring-steel rod wound into a spiral.

7. Leaf Spring Made up of flat strips of spring steel bolted together
A shackle fastens the spring eye to the frame or body and allows the spring to change length when bent.
How do leaf springs work video

8. Torsion Bar Made of a large spring-steel rod
One end is attached to the frame, the other end to the control arm
Bumps in road force wheel to twist the torsion bar
How does Torsion Bar work Video

9. The bar resists twisting action and acts like a conventional spring
Torsion Bar
The bar resists twisting action and acts like a conventional spring

10. Suspension System
Components

11. Control Arms
Used to hold the steering knuckle, bearing support, or axle housing in position as the wheel moves up and down

12. Ball Joints Connections that allow limited rotation in every direction
Filled with grease for lubrication

13. Shock Absorbers
One end is connected to the body or frame, and the other is connected to the axle or control arm
When compressed or extended, oil inside the shock is forced through small passages, dampening spring action

14. Track Rod
Used on the rear axle to prevent side-to-side movement during cornering

15. Sway Bar (Stabilizer Bar)
Used to keep the body from leaning excessively in sharp turns
When the body leans, it twists the bar

16. MacPherson Strut Suspension
Uses only a lower control arm and a strut to support each wheel assembly
The most common system in use on late-model cars
Macpherson Strut Inspection Video

17. Strut Assembly

18. MacPherson Strut Suspension
The top of the strut is fastened to the reinforced body structure, which supports the weight of the car

19. Front Strut Suspension
Suspension Basics: Alignment Video

20. Rear Strut Suspension

21. Rear Suspension Systems The rear axle housing may be solid
Non-independent suspension
Rear swing axles can also be used
Independent suspension

22. Nonindependent Rear Suspension
Solid axle housing for a rear-wheel-drive vehicle
Video Explanation

23. A solid axle that does not drive wheels
Dead Axle
A solid axle that does not drive wheels

24. Independent Rear Suspension
Trailing-arm design

25. Independent Rear Suspension
This differential is mounted to the frame

26. Air Suspensions How air suspensions systems work video
Cali Faces Low rider air suspension video
Low-rider Show in LA