REVISED:POP NOISE WHEN BRAKING FORE / AFT SHIFT OF FRAME

ENGINE CRADLE NOISE

MODELS AFFECTED: ALL 1984-86 CENTURYS AND 1984-85 SKYLARKS --------------- Dealer Service Bulletin 85-2-4 has been revised to include 1986 Centurys below the following VIN breakpoints:

PLANT VIN

Doraville 1G4AL353OGD443229

Oklahoma City 1G4AL19R4G6442527

Tarrytown 1G4AH19X7GT459369

Some 1984-86 "A" and 1984-85 "X" cars may exhibit a popping type noise during breaking and acceleration. The popping noise, caused by a fore and aft shifting of the cradle, can be felt as "oil canning" in the floor pan. (The popping noise should not be confused with a "click" or "clunk" felt in the steering wheel -- covered in Dealer Service Bulletin 84-3-9). Another similar sounding noise, "crunching", could be caused by loose cradle mount bolts. Torque should be 85 ft. lbs. (115 Nm).

If the noise is still present after tightening the cradle bolts, it can be corrected by installing shims on both rear cradle mount insulators, as shown in illustration. The intent of this fix is to create an interference fit using shims. Multiple shims may be used if necessary.

Shims may be fabricated from any available steel or brass shim stock. Thickness should be approximately .025" to .040".

The following procedure should be followed when installing shims:

1. Support cradle with a jack stand on the rear crossmember.

2. Remove one (1) rear cradle bolt at a time and lower jack stand enough to remove pressure from the mount.

CAUTION:

DAMAGE TO THE STEERING INTERMEDIATE SHAFT COULD RESULT IF THE CRADLE IS LOWERED MORE THAN REQUIRED TO FREE THE MOUNT.

3. Form shim to mount as shown and reinstall mount. Some rubber lube may be required to ease assembly.

4. Reinstall mount bolt. Torque to 85 ft. lbs. (115 Nm).

5. Repeat above procedure on other rear corner.

Warranty Information

Labor Operation Number: E1040 Labor Time: .5 hours Trouble Code: 92

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.