Brake - Pulsations

86chevy11

Number: 86-84

Section: 5

Date: May, 1986
Subject: BRAKE PULSATIONS


Model and Year: ALL MODELS
TO: ALL CHEVROLET DEALERS


Brake pulsations are normally the result of uneven rotor thickness or an out of round condition in a brake drum. Pulsations can also be caused by a rust build up on the rotor. Under certain conditions, the exterior of the rotor may rust. This would normally not occur unless vehicle was parked for a few days and corrosive conditions were present. If the rotor exterior does rust, the area under the brake pads usually remains rust free. The difference in friction between the rust and unrusted areas can cause pulsation for several stops, but will improve as the linings scrub the rust off the rotor.

Normally, two or three stops will return the system to normal. Under adverse rust conditions, as many as five or six stops may be required. Usually this condition will correct itself. It is, however, important that the customer understand what is happening should you receive a comment on this condition.