The lower control arm is a two-piece welded unit with a riveted ball joint. The rear lower control arm pivot uses a non-replaceable bushing. The front bushing mounts vertically and can be replaced.
The lower control arm uses two types of bushings. The horizontally mounted (rear) bushing is not serviced separately. Service this bushing by replacing the entire lower control arm.
The front bushing is mounted vertically in the control arm. This bushing can be serviced but GM recommends their special tools be used to remove and replace this bushing. The tool set is basically components that look similar to sockets. A heavy bolt passes through the assembly to press the old bushing out and also press the replacement bushing back into place. If these special tools are not available, a hydraulic press, if used with care, could possibly be substituted. Another solution is take the control arm to an automotive machine shop to have the bushing replaced.
- Remove the lower control arm using the procedures found in this section.
- Jig together the special tools required to press the bushing out. GM recommends their J 2147-27 puller bolt be used with bushing receiver J 21474-5, installed with the larger diameter end over the bushing against the control arm. Bushing remover J 41014-1 is installed with the large end facing the bushing. Special nut J 21474 threads onto the puller bolt. Tighten the nut until the bushing is driven out of the control arm.
- Remove the puller tools.
- Reassemble the puller tools so that the service replacement bushing will be pressed into the control arm.
- Lubricate the bushing with soap and water and press it into the control arm.
- Remove the puller tools.
- Install the control arm using the procedures found in this section.
Removal & Installation
- Raise and safely support the vehicle by the frame. Allow the control arms to hang free.
- Remove the tire and wheel assembly.
- Remove the outer tie rod end from the steering knuckle using the procedure found later in this section.
- Disconnect the stabilizer shaft link (bolt) from the control arm.
- Detach the ABS speed sensor jumper harness.
- Remove the control arm mounting bolts.
- Take note of the orientation of the cotter pin. Cotter pin placement may seem insignificant, but at assembly, the bent ends of the cotter pin must not face the ABS wheel speed sensor or the drive axle. Remove the cotter pin and loosen, but do not remove the nut from the ball joint stud.
- Separate the ball joint stud from the steering knuckle using a ball joint press-type tool. Leaving the ball joint stud nut in place protects the threads on the ball joint stud when the tool presses the stud from the steering knuckle. Do not use a so-called "pickle fork" or any type of wedge to force the ball joint stud from the steering knuckle.
- Remove the control arm from the frame.
- Clean all parts well. If the ball joint is being replaced, use the procedures found in this section.
- Install the control arm to the frame and install the bolts and nuts. Do not final tighten until the weight of the vehicle is supported by the control arms.
- Carefully guide the ball joint stud into the bore in the steering knuckle and tighten down the nut. Tighten the nut to 40 ft. lbs. (55 Nm). Align the slots in the nut with the cotter pin hole in the ball joint stud by tightening the nut. DO NOT loosen the nut to align the holes for the cotter pin. Install a new cotter pin. The bent ends of the cotter pin MUST NOT face the ABS wheel speed sensor or the drive axle.
- Connect the steering tie rod end to the steering knuckle using the procedures found in this section.
- Install the stabilizer shaft link bolt to the control arm. Torque the nut to 17 ft. lbs. (23 Nm).
- Assemble the ABS wheel speed sensor harness.
- Tighten the control arm mounting nuts with the weight of the vehicle supported by the control arms. Tighten the mounting nuts to 83 ft. lbs. (113 Nm).
- Install the wheel and tire assembly.
- Lower the vehicle.
- Take the vehicle to a reputable repair shop to have the wheel alignment checked and adjusted, if necessary.