Brakes - Pulsations and Rotor Surface Refinish: Overview
88chevy16Number: 88-312-5
Section: 5
Date: AUGUST, 1988
Subject BRAKE PULSATIONS AND DISC BRAKE
ROTOR SURFACE REFINISH
Model and Year 1982-88 CHEVROLET MODELS
TO: ALL CHEVROLET DEALERS
On today's vehicles the primary reason for brake pulsation is variation in the thickness of the rotor, which generally occurs after some mileage.
The causes of rotor thickness variation tend to occur while the vehicle is in motion and the brake pedal is in the unapplied position. Three events must occur simultaneously:
1. The rotor/bearing system runout must be out of specification enough to produce high spots on the rotor face in relation to the caliper.
2. There must be a condition of caliper drag which causes the inboard and/or outboard shoe to rub on the rotor high spots.
3. The lining material must be sufficiently abrasive to cause wear on the high spots and therefore to develop rotor thickness variation after accumulated mileage.
Following is a discussion of each of these events along with information about the conditions which can contribute to each.