For 1990-2009 cars

# DISC BRAKE NOISE GUIDELINES CONCERNING NOISE

#### MODELS AFFECTED: ALL

The Disc Brake system used on vehicles today was designed and developed to meet a diverse array of stringent requirements while providing an optimum level of performance under a wide range of vehicle operating conditions. The design criteria includes government requirements, service life, space limitations, noise level, heat transfer and cooling, stopping ability, pedal effort and feel, fade resistance and environmental effects.

The choice of brake pads is ultimately a balanced choice, but priority must be given to those criteria which affect braking performance under the Federal Motor Vehicle Safety Standards. As a result, a certain amount of brake noise can result. The brake pads used on today's vehicles may cause an occasional and intermittent high-pitched squeak or squeal when brakes are applied with light or moderate pressure. If the brake system is functioning correctly and it is the judgement of the dealership's service department that the demonstrated condition is normal brake noise, the customer should be assured that this is an operating characteristic of disc brakes and no repair attempted. Efforts to completely eliminate these noises are frequently temporary.

All brake noises should not be arbitrarily considered normal. They should be diagnosed as outlined in the Service Manual. An example of a similar noise requiring corrective action is the constant versus intermittent high-pitched squeal that is emitted by the disc brake wear warning sensor when brake pads are excessively worn.

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.