DeVille V6-260 4.3L DSL (1985)
Brake Caliper: Technical Service Bulletins
Conditions and Causes
FIGURE 1 - HOLE WHEEL NUT TIGHTENING SEQUENCE
CONDITION
Some vehicles may exhibit a pulsating or vibrating condition (roughness) when the brakes are applied. This bulletin specifically addresses pulsation
resulting from disc brake rotor thickness variation. It should be recognized that vibration perceived by the customer may be induced by rear brakes or
may also be due to vibration from other components such as drivetrain, tires, and/or road surface conditions.
CAUSES
One possible cause of rear drum brake pulsation is an out-of-round condition (radial run out) in a rear drum. This may occur during manufacture,
however, a brake drum may also be distorted if pried off, struck with a hammer, or dropped during routine brake inspection or service.
Causes of rear brake pulsation on vehicles equipped with four-wheel disc brakes are essentially the same as those described for front brake pulsation.