For 1990-2009 cars

# BRAKE SYSTEM CHANGE/ IMPROVED ASSIST

#### MODELS AFFECTED: 1988 SKYHAWKS 1988 SKYLARKS

1988 Skyhawks and Skylarks beginning with the following vehicle identification numbers (VIN) at the assembly plants listed will be equipped with a different brake master cylinder, brake booster assembly and brake caliper assembly.

#### MODEL VIN BREAKPOINTS ----- --------------- Somerset/Skylark JMO11292 Skyhawk JK409094

The changes to the brake system were incorporated to provide an improved pedal feel and increased booster assist on initial brake apply.

#### PARTS USAGE

The new caliper part numbers listed below must be used to service ALL 1988 Skyhawks and Skylarks, regardless of VIN.

The NEW brake booster and master cylinder part numbers listed in this bulletin MUST be used to service only those Skyhawks and Skylarks models produced, beginning with the VIN breakpoints provided.

#### NOTICE: Vehicles built prior to the VIN breakpoints MUST be serviced with the prior brake booster and brake master cylinder part numbers listed in this bulletin. Mixing the new booster and master cylinder parts with prior parts on early built (prior to VIN breakpoints) vehicles may result in a brake application requiring increased pedal travel to stop the car.

#### PARTS INFORMATION

1988 NEW 1988 OLD PART NUMBER PART NUMBER ----------- -----------

Caliper 18015752 (Left) 18011667 (Left) 18015753 (Right) 18011668 (Right)

Booster 18015498 (Code NT) 18013875 (Code LF)

Master Cylinder 18015760 (Code NT) 18014370 (Code DL)

#### PARTS IDENTIFICATION

The new brake booster part number listed in this bulletin can be identified by the broadcast code 'NT' printed on the bar code label which is attached to the part. See illustration, View A.

The new master cylinder part number listed in this bulletin can be identified by a broadcast code of 'NT' stamped on the aluminum housing. See View C. The broadcast code of'NT' is also printed on the bar code label attached to the rear of the brake fluid reservoir, View B. The brake booster, master cylinder, and brake fluid reservoir MUST all have a broadcast code of 'NT' on all vehicles built after the VIN breakpoints listed in this bulletin.

#### WARRANTY INFORMATION

When submitting a warranty claim, use existing labor operation and times.

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.