Brakes - Squeal/Squeak, Front & Rear: Overview

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Models: (see below)

Section: Brake

Classification: BR89-005

Bulletin No.: TS89-106

Date: July 20, 1989


FRONT AND REAR BRAKE SQUEAL


APPLIED MODEL: 1985-88 Maxima (U11)
1987-89 Stanza (T12)
1984-89 300ZX (Z31)


SERVICE INFORMATION

This bulletin provides technical information, repair procedures and parts information to resolve front and rear brake squeal on the Applied Models.

CAUSE: A brake component vibrates at high frequency.

When the pad material is pressed against tne turning rotor, it sticks to the metal surface for an instant, then slides, then sticks again. This is like a rubber eraser dragged along a table top, or fingernails dragged across a chalk board. This stick/slip action causes a very high frequency vibration in the brake system. Sometimes, one of the brake system components can vibrate hard enough to cause an audible, annoying squeal or squeak noise. Brake squeal noise usually occurs under a very narrow range of conditions of vehicle speed, brake pedal force, brake temperature and pad/rotor condition.

Brake squeal is not caused by "glazed" pads or rotors. It is normal for a rotor and pad to have a shiny, polished appearance. Replacing pads and machining the rotors to remove this polished appearance may resolve squeal noise temporarily, but the noise will return after the pads and rotors break in and regain their polished appearance.

It is very difficult to prevent brake squeal under every possible brake operating condition, especially on a performance oriented car whose brakes must operate efficiently under a wide range of conditions. Nissan uses two methods to reduce brake squeal:

1) Designing brake components that do not vibrate at the same frequecy as squeal or squeak noise.

2) Installing rubber-covered brake pad shims to absorb vibration energy.