This information should be added to the 1989 through 1992 Firebird Service Manuals. These changes affect Section 5B3, Rear Disc Brake Caliper Assembly.
To properly adjust parking brake free-travel, it is essential that the parking brake cable be disconnected from the lever and the parking brake lever return spring be removed. Then follow the steps listed in the Service Manual.
If the parking brake cable is not disconnected and the parking brake lever return spring is not removed, the adjustment will not be accurate.
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.