Suspension (Rear) - Thud/Clunk Noise

91pontiac07

Bulletin Number: 91-3-18
Reference Number: 133403
Publish Date: 8/91


Subject: REAR SUSPENSION AUXILIARY SPRING
THUD/CLUNK (LOWER ATTACHING BRACKET POSITIONING)

Models
Affected: 1989-91 GRAND PRIX MODELS


Condition: Some 1989-91 Grand Prix models equipped with auxiliary rear springs may exhibit a thud/clunk type noise coming from the rear of the vehicle that is audible in the passenger compartment. This condition is most apparent after a harsh/sharp road input such as a chuck-hole/ speed bump.

Cause: Auxiliary rear spring lower attaching bracket not in full contact with rear spindle rod. Under certain operating conditions lower attaching bracket may flex and contact spindle rod resulting in thud/clunk noise.

Correction: Following service procedure indicated below, insure that the auxiliary rear spring lower brackets are properly seated on spindle rods.

Service Procedure:

1. Raise vehicle and support in such a manner that rear suspension is extended in a full downward position.

2. Inspect both right and left hand auxiliary spring lower brackets to insure they are in contact with spindle rods utilizing a .002" feeler gage.

3. If a bracket is not in contact, loosen lower bracket to spindle rod bolt a maximum of two revolutions. Let bracket position itself on spindle rod and re-torque bolt(s) to 46 N-m (36 lbs.ft.).


CAUTION: THE AUXILIARY SPRINGS ARE UNDER COMPRESSION AND BOLTS MUST NOT BE REMOVED. DOING SO MAY RESULT IN PERSONAL INJURY.

4. Lower vehicle.

Labor Operation Number: T1752

Labor Time : 0.3 Hours