Document xYMyb4M47gk30ZYz1n1eD10G

LESSON ONE-MODULE 2 Barrel Shape Drums BRAKE SYSTEM SERVICE Out-of-Round Drums Item Description 1 Barrel Shape 2 Lining 3 Brake Drum 4 Shoe Out-of-Round Drum BSR035-A Out-of-Round brake drums will usually cause a pulsat ing brake pedal. This condition can be found by measuring the drums diameter in several places. The out-of-round condition forces the brake shoes in and out as the drum rotates. A drum that shows excessive wear at the center of its friction surface is said to be barrel shaped. The cause is usually extreme braking pressure. This condition can be detected by brake shoes that are rounded from side-to-side, and confirmed by measuring the lip of the drum and the center of the friction surface, then comparing the measurements. If the barrel shape cannot be safely machined out of the brake drum, then the drum must be replaced. 44 September, 2005 Brake System Diagnosis and Repair