ELECTRIC VACUUM PUMP NOISE AND VIBRATION-REPLACE GROMMETS

MODELS AFFECTED: 1985 FWD DEVILLES

Some 1985 FWD Devilles and Fleetwoods built before B.C. Number 314999 may experience a buzzing or moaning noise accompanied by vibrations in the steering wheel, instrument panel and floor panel. The magnitude of the noise and vibration increases with ambient temperatures less than 20 DEG F. The cause of these conditions are the three rubber mounting grommets which are used to isolate the electric vacuum pump from the rest of the vehicle (see Figure 1), contact between the front LH wheelhouse splash panel shield and the vacuum supply hose (see Figure 2), and possible misalignment between the vacuum pump and the rear leg of the vacuum pump mounting bracket. During cold ambient conditions, less than approximately 20 DEG F, the rubber grommets become hard and transmit noise and vibrations to the vehicle. To repair these conditions, it is necessary to replace the three rubber grommets with softer rubber grommets, and eliminate contact between the vacuum hose and splash panel. The new grommets are available in service kit P/N 22055187. To replace the grommets and eliminate contact between the vacuum hose and splash panel, follow the procedure below:

1. Hoist car.

2. Remove the left side of the deflector (air dam) to obtain access to the vacuum pump.

3. Remove the three vacuum pump mounting screws.

4. Remove the three grommets from the vacuum pump (see Figure 1).

NOTE: The grommets can be removed without disconnecting the vacuum lines and electrical connector from the vacuum pump.

5. Install the new grommets contained in service kit P/N 22055187 (see Figure 1).

IMPORTANT: Make sure the grommets are installed in the correct orientation as shown in Figure 1.

6. Install the two front vacuum pump mounting screws. Make sure the screws are installed perpendicular to the mounting bracket.

7. Check the rear grommet and bracket hole alignment. If the holes do not line-up, bend the rear bracket leg to align the holes.

IMPORTANT: The grommet and bracket screw holes must align properly to prevent cocking of the vacuum pump mounting screw, which will cause vacuum pump noise and vibrations to ground through the grommet to the bracket and to the rest of the car.

8. Install the rear vacuum pump mounting screw.

9. Remove the wheelhouse splash panel shield which is held by a reusable drive nail fastener and a reusable Christmas tree fastener.

10. Support the splash panel in a vise and remove the corner of the splash shield as illustrated in Figure 2. A metal hacksaw works well for cutting the splash shield.

11. Install the splash panel.

12. Install the left side of the deflector (air dam).

For warranty purposes, use labor Operation Number T6121 at .4 hour.

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.