ROAD NOISE IN PASSENGER COMP. (INSTALL DAMPENING PACKAGE)

SUBJECT: ROAD NOISE IN PASSENGER COMPARTMENT (INSTALL DAMPENING PACKAGE)

VEHICLES AFFECTED: 1985-1991 'C'

Some 1985-1991 DeVille and Fleetwood Coupes may experience road noise emitting from the rear seat or rear sail panel areas on coarse road surfaces (i.e., worn or stud-damaged concrete). This sounds very similar to wheel bearing noise. Follow the procedure below before replacing a hub and bearing assembly.

To repair this condition install dampening package, P/N 25600885, on top of the left and right rear strut towers (inside the rear compartment area) using the following procedure:

1. Remove speaker enclosures from rear shelf.

IMPORTANT: Additional trim removal is not necessary.

2. Grind the ends of the rear seat shoulder harness retractor bolts flush where they protrude down from the rear shelf.

3. Position left and right dampener weights on top of the rear shock towers. (Dampeners are marked LH for left and RH for right.) Install one stud extender on the rearmost strut mount stud on each side on top of the existing nut by passing it through the hole in the dampener weight and running it down by hand. Then, lift the weight up so the stud flats are exposed and torque to 12-15 N.m (9-11 ft.lbs.) with an open- end wrench.

4. Install washers and M-14 nuts and torque to 20 N.m (15 ft.lbs.). Reinstall the main speaker enclosures.

Use the most applicable Labour Operation and Time from the Canadian Labour Time Guide.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.