Document yrGO0BjvM58Z2aQr91rojXDv4

BRAKE SYSTEM SERVICE Eccentric Drums LESSON ONE-MODULE 2 Bell-Mouth Eccentric Drum BSR036-A Bell-Mouthed Drum Another cause of a pulsating pedal is an eccentric brake drum. This condition can also be found by measuring the brake drum in several places. An eccentric brake drum will be out-of-round more on one side than the other. Item Description 1 Lining 2 Brake Drum 3 Shoe 4 Bell-Mouthed Both out-of-round and eccentric drum conditions can be caused by the driver applying the parking brake when the drum is overheated. Improper lug nut torque, or tightening the lug nuts in an improper sequence can also cause these problems. A bell-mouth condition is where the open end of the brake drum distorts outward due to high braking temperatures, and excessive braking pressures. The condition can be verified by measuring the drum at different points. A bell-mouth drum is indicated when the brake shoes are worn at an angle with the low point on the outer edge and the high point at the inner edge. Brake System Diagnosis and Repair September, 2005 45