REAR DISK BRAKE MOAN (REPLACE DAMPERS)

SUBJECT: REAR DISC BRAKE MOAN (REPLACE DAMPERS)

VEHICLES AFFECTED: 1993 "F" MODEL WITH RPO J65

APPLICATION:

1993 "F" Car's with RPO J65

CONDITION:

Some owners of 1993 "F" cars may experience a moan type noise from vehicles with RPO J65 (rear disc brakes).

CAUSE:

Stick slip of rear friction material on rotor during light braking sets up sympathetic vibration (moan) of rear suspension and body structure components.

CORRECTION:

Some vehicles built before VIN's P2101098 Chevrolet and P2200768 Pontiac may have been built with dampers that were not to specification. If a vehicle exhibits brake moan, replace the dampers with P/N 10224765. Re- torque bolts to 50 N.m (37 Lb.Ft.). Since new pads may tend to intensify the moan condition, it is NOT recommended to replace the rear pads when changing the dampers.

NOTICE: The effects of the out-of-spec dampers may not occur in the span of a quick test drive due to low pad temperatures, moisture, etc. To avoid lengthy test drives of customer vehicles, (when a vehicle falls within the VIN's listed above) replace the dampers even when the condition is not apparent.

CREEP-GROAN:

This rear brake moan should not be mistaken with creep-groan which happens when brake pedal pressure is slowly released on a stopped vehicle. As the vehicle starts to "creep" forward with slight brake pedal pressure still applied, the pads may vibrate/slip on the rotor and there is a distinct "groan" type noise until pedal pressure is released.

For vehicles repaired under warranty use:

Labour Time: 0.3 HRS

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.