GM Cadillac 1967-1989 Repair Guide

FRONT SUSPENSION

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See Figures 1, 2 and 3

The front suspension is designed to allow each wheel to compensate for changes in the road surface level without appreciably affecting the opposite wheel. Each wheel is independently connected to the frame by a steering knuckle, ball joint assemblies, upper and lower control arms. The control arms are specifically designed and positioned to allow the steering knuckles to move in a prescribed three dimensional arc. The front wheels are held in proper relationship to each other by two tie rods which are connected to steering arms on the knuckles and to an intermediate rod.

On rear wheel drive models coil chassis springs are mounted between the spring housings on the frame or front end sheet metal and the lower control arms. Front wheel drive models (through 1985) use torsion bars instead of coil springs. The front end of the torsion bar is attached to the lower control arm. The rear of the torsion bar is mounted into an adjustable arm in the torsion bar crossmember. The standing height of the car is controlled by the adjuster bolt and nut that positions the adjuster arm. Ride control is provided by double, direct acting, shock absorbers (mounted inside the coil springs on rear wheel drive models) and attached to the lower control arms by bolts and nuts. The upper portion of each shock absorber extends through the upper control arm frame bracket and is secured with two grommets, two grommet retainers and a nut. As of 1986, front wheel drive models are equipped with MacPherson-type struts. The struts, used on both sides, are a combination spring and shock absorber with the outer casing of the shock actually supporting the coil spring at the bottom and thus forming a major structural component of the suspension. The steering knuckle/wheel hub assembly is attached to the bottom of the strut. A strut mounting bearing at the top and a ball joint at the bottom allow the entire strut to rotate during cornering maneuvers.

Side roll of the front suspension is controlled by a spring steel stabilizer shaft. It is mounted in rubber bushings which are held to the frame side rails by brackets. The ends of the stabilizer are connected to the lower control arms by link bolts isolated by rubber grommets.

The upper control arm is attached to a cross shaft through isolating rubber bushings. The cross shaft, in turn, is bolted to frame brackets.

A ball joint assembly is riveted to the outer end of the upper arm. It is pre-loaded by a rubber spring to insure proper seating of the ball in the socket. The upper ball joint is attached to the steering knuckle by a torque prevailing nut.

The inner ends of the lower control arm have pressed-in bushings. Bolts, passing through the bushings, attach the arm to the frame. The lower ball joint assembly is a press fit in the arm and attaches to the steering knuckle with a torque prevailing nut.

Rubber grease seals are provided at ball socket assemblies to keep dirt and moisture from entering the joint and damaging bearing surfaces.



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Fig. Fig. 1: Common front suspension on a rear wheel drive vehicle



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Fig. Fig. 2: Common front suspension on front wheel drive vehicles through 1985



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Fig. Fig. 3: Front suspension on the 1986-89 front wheel drive models

 
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