For 1990-2009 cars

# DISC BRAKE NOISE GUIDELINES/DESCRIPTIONS

DISK BRAKE NOISE - GUIDELINES CONCERNING NOISE

#### VEHICLES AFFECTED: ALL MODELS WITH DISC BRAKES ------------------

The disc brake system used on vehicles today was designed and developed to meet many different but very strict 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 Canadian Motor Vehicle Safety Standards. As a result, a certain amount of brake noise can result. The brake pads used on today's vehicle 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 judgment 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 should be attempted.

Efforts to eliminate completely the occasional and intermittent noises that are judged to be normal are frequently temporary. All brake noises should not arbitrarily be considered normal however. They should be diagnosed as outlined in the appropriate model year service manual. An example of a similar noise requiring corrective action is the constant 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.