GM Service Manual Online
For 1990-2009 cars only

Front Suspension


Object Number: 157081  Size: LF
(1)C Series (except C3500HD)
(2)K Series
(3)C Series (C3500HD)

The front suspension allows each wheel to compensate for changes in the road surface without affecting the opposite wheel. Each wheel, except C3500HD, independently connects to the frame with a steering knuckle, ball joint assemblies, and upper and lower control arms.

Two tie rods connect to steering arms on the knuckles and to a relay rod. These operate the front wheels.

Two-wheel drive C Series models (1), except C3500HD, have coil chassis springs. These springs are mounted between the spring housings on the frame and the lower control arms. Shock absorbers mount inside the coil springs. The coil springs attach to the lower control arms with bolts and nuts.

The upper part of each shock absorber extends through a frame bracket. Two grommets, two grommet retainers, and a nut secure the upper part of the shock to the frame.

A spring steel stabilizer shaft controls the side roll of the front suspension on some models. This shaft is mounted in rubber bushings that are held by brackets to the frame side rails. The ends of the stabilizer shaft connect to the lower control arms with link bolts. Rubber grommets isolate these link bolts.

A ball joint assembly is riveted to the outer end of the upper control arm. A castellated nut and a cotter pin join the steering knuckle to the upper ball joint.

The inner ends of the lower control arm have pressed-in bushings. The bolts pass through the bushings and join the arm to the frame. The lower ball joint assembly is a press fit in the lower control arm and attaches to the steering knuckle with a castellated nut and a cotter pin.

Ball socket assemblies have rubber grease seals. These seals prevent entry of moisture and dirt, preventing damage to the bearing surfaces. And, all ball joints have grease fittings for routine maintenance.

Four-wheel drive (2) K Series models have a front suspension that consists of the following components:

    • Control arms
    • Stabilizer shaft
    • Shock absorber
    • Torsion bar (right and left side)

Torsion bars replace the conventional coil springs. The front end of the torsion bar attaches to the lower control arm. The rear of the torsion bar mounts into an adjustable arm at the torsion bar crossmember. This arm adjustment controls the vehicle trim height.

K Series models have sealed front wheel bearings. These bearings are pre-adjusted and need no lubrication. Heat treatment may create darkened areas on the bearing assembly. This discoloration does not signal a need for replacement.

A heavy-duty front suspension (3) is standard on the C3500HD model. This suspension is centered around a solid I-beam axle that includes taper leaf springs, shock absorbers, and a stabilizer shaft.