Brakes - Vibration and Noise in Rear
88buick06Bulletin: 88-5-9
Date: April '88
Ref. No.: 88-139-5
Corp. Ref. No.: 815002
SUBJECT: REAR BRAKE VIBRATION AND NOISE
MODELS AFFECTED: 1986-1988 RIVIERAS
Some 1986-1988 Rivieras equipped with steel wheels and wire wheel disc (option code N91) may experience a minor vibration and/or noise from the rear of the vehicle when braking. The noise (boom) and vibration will appear in the 45-35 mph range on deceleration and may be more noticeable in higher ambient temperatures or on smooth road surfaces.
This condition may be caused by distortion in the rotor braking surfaces. To repair this condition, use the following procedure:
Installation:
1. Remove the rear rotors as described in the appropriate Service Information Manual.
2. Clean the hub flange and rotor mating surfaces of any corrosion or foreign material.
3. Install the shim, P/N 1648437 (two required per car), on the hub flange and place the locating tabs in the hub and bearing bolt access hole (large), Refer to Figure 1.
4. Reassemble the rear brakes and install new encapsulated caliper mounting bolts, P/N 25524723, and torque to 113 N-m (80 ft.lbs., four required per car).
5. Install wheels and torque to 140 N-m (100 ft.lbs.).
6. If some noise is still present, re-index wheel assembly on hub and road test. If noise is still noticed, replace rear wheel assemblies.
WARRANTY INFORMATION
Labor Operation Number: T6277
Labor Time: .8 hour
Trouble Code: 92