IMPROVED BRAKE PEDAL FEEL NEW BRAKE BOOSTER RELEASED

SUBJECT: IMPROVED BRAKE PEDAL FEEL

MODELS: 1990-91 K1 TRUCKS

Some customers may comment of hard brake pedal or lack of assist on some 1990-91 K1 trucks equipped with JB3 brakes. During the 1991 model year, a new larger displacement brake vacuum booster will be installed in production on the above trucks. The new booster is being installed to improve power assist during braking and to improve the "feel" of the brakes, especially for customers who operate their vehicle heavily loaded most of the time.

Customers with vehicles built with the old boosters who operate vehicles heavily loaded may prefer the improved brake pedal feel of the new booster. If so the new brake booster can be installed on vehicles with this condition. When installing the new booster, follow the procedure in Light Duty C/K Service Manuals X-9031 and X-9131, Section 5A.

VEHICLES INVOLVED

Technicians can identify the old smaller displacement booster by a white tag on the booster. The letters BM will be printed in the tag. The new service booster has the letters HR printed in the tag.

VIN BREAKPOINTS

Fort Wayne GMC 1GTDC14HXMZ519105 Chevrolet 1GCDK14Z3MZ168422

Oshawa Not involved

Pontiac East GMC 1GTGK24K1ME518837 Chevrolet 1GCEK14CXME159028

SERVICE PARTS INFORMATION

Part Number Description ----------- ------------ 18012114 Brake Booster

Parts are currently available from GMSPO.

WARRANTY INFORMATION

For vehicles repaired under warranty use: Labor Operation: H1220 Labor Time: 1.0 hr.

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.