Basic Suspension System

   Fig. 8. 1 illustrates the basic parts for suspension system.

    Control arm - movable level that fastens the steering knuckle to the vehicle'sbody or frame

    Steering knuckle - provides a spindle or bearing support for the wheel hub，bearings，and wheel assembly

    Balljoint - movable connection that allows the control arm to move up and downwhile allowing the steering knuckle to swivel from side to side

    Spring - supports the weight of the vehicle, permits the control arm and wheel tomove up and down

    Shock absorber or damper - keeps the suspension from continuing to bounce afterspring compression and extension

    Control arm bushing - sleeve that allows the control arm to swing up and down onthe frame