Control Arm: Description and Operation
LOWER CONTROL ARMDESCRIPTION
The lower control arm is mounted to the front suspension crossmember using a pivot bolt through the center of the front pivot bushing, and the front suspension cradle crossmember reinforcement traps the rear bushing in the crossmember.
The lower control arm is an iron casting with two rubber bushings and a ball joint. The lower control arm front bushing is the spool type and is pressed into the lower control arm. The standard (Low-line) lower control arm rear bushing is a push-on bushing that is pushed over a stem on the rear of the lower control arm. The optional (High-line, Premium, Sport) lower control arm rear bushing is a hydro-bushing that is pressed on. It has liquid filled voids that provide more effective dampening than the standard bushing. Vehicles with rear hydro-bushings utilize a different lower control arm than vehicles with standard bushings. They have a straight slightly tapered round stem where the hydro-bushing is mounted whereas the standard arm has a straight stem with a squared knob on the end to retain the bushing.
The lower control arm ball joint is pressed into the outer end of the arm. The ball joint has a tapered stud and retainer nut for fastening it to the steering knuckle.
OPERATION
The lower control arm supports the lower end of the steering knuckle and allows for the up and down movement of the suspension during the jounce and rebound travel. The lower control arm ball joint connects the arm to the steering knuckle.