1. Suspension Systems
Consumer Auto

2. What is a Suspension System?
It supports the weight of the car
It keeps tires in firm contact with road
It prevents body roll when cornering
It keeps the wheels in alignment

3. Typical Suspension System Parts
Control arm
Spring
Shock
Ball joint
Knuckle

4. Control Arms Can be an arm that in the shape of an “A” (purple)
Some are a heavy duty rod
Used to keep the tires in alignment

5. Springs Front springs are usually coil springs (10)
Rear springs can be coil or leaf springs (11)
Some springs are a round bar called a torsion bar
Used to hold the weight of the car

6. Ball Joint
Mounted in the control arm, it lets the tire turn as well as go up and down at the same time
The other end mounts to the spindle

7. Steering Knuckle (Blue Green)
Holds the tire to the car using a spindle
Attaches to the lower control arm and the strut or upper control arm
Connects to the tie rods for steering

8. Shock Absorber Stops the car from bouncing excessively
Helps prevent rapid tire wear
Does not support the weight of the car

9. Types of Suspension Systems
Short Arm/Long Arm McPherson Strut

10. Short Arm/Long Arm Suspension Parts
Upper & lower control arms
Upper & lower ball joint
Steering knuckle
Coil spring
Shock
Stabilizer bar & link

12. Short Arm/Long Arm Suspension Operation
Control arms mounted to frame and the steering knuckle
Upper arm shorter than lower, making them unequal in length
Provides a way for the tires to maintain traction with the road when the car goes over bumps

13. McPherson Strut Suspension Parts
Coil spring
Lower control arm
Knuckle
Stabilizer bar
Strut rod

15. McPherson Strut Operation
Coil spring & shock are combined
The upper control arm is replaced by the McPherson strut
Less parts and weight which gives better gas mileage
Not a heavy duty suspension system
Used on smaller cars

16. Shock Absorbers Used on SLA systems Dampens the rebound of the spring
Stops spring oscillations
Provides resistance one way (extending)
Can wear out

17. Shock Absorber Inspection
Look at the shock for signs of damage
Look for leaking fluid from the ram end
Test the operation by jumping on the car to see if it bounces more than once
Replace the shock if it is bad
Replace in pairs

18. Air Shocks Used to adjust height or help sagging springs Used on rear
Air added and released manually

19. Automatic Load Leveling Systems
Usually a four wheel system
Has an air pump and sensors that monitor the ride height
Air added & released automatically as needed

21. Active Suspension Systems
Springs & shocks replaced with actuators
Actuators work by hydraulics
They adjust the height of the car and the stiffness of the ride
Sensors automatically correct ride without input from the driver

23. Review Do shocks correct ride height? What are the 2 types of springs?
Active suspension replaces springs and shocks with this part.
SLA stands for what?
What part does the McPherson strut suspension not have?

24. Review What is the purpose of the ball joint?
Why do we need springs in the suspension?
In what type of car is McPherson strut suspension used?
What is one reason why we have suspension systems
The spindle attaches to what 2 parts?