CATBE501

1Poor bedding-inMain Reasons:• Drum diameter is larger than liningradius• Bedding-in period for the lining wastoo short• Drum wearPossible Consequences:• If the wear pattern differs acrossthe axle, vehicle pull can result;also excessive brake noise• Low deceleration4Circumferential groovesMain Reasons:• Poor drum condition• Improper preparation with a wirebrush, shoe grinder or similarPossible Consequences:• Vehicle pull may occur if there isa different wear pattern on theopposite axle end• Insufficient deceleration andexcessive noiseMain Reasons:• Lining radius is larger than actualdrum diameter• Bedding-in period for the lining wastoo shortPossible Consequences:• Vehicle pull and excessive brakenoise may occur• Low deceleration5Grooved lining surfaceMain Reasons:• Small loose particles in the brake• Insufficient drum cleaningat replacementMain Reasons:• Bedding-in period for the liningwas too short• Drum wearPossible Consequences:• Very high lining and drum wear• Squeal2Possible Consequences:• Either low or very high deceleration,with high deceleration the liningsmay lock on to the drum• If the wear pattern differsacross the axle, vehicle pulland excessive noise can resultSteps in the lining surfaceMain Reasons:• There may be a step in the brakedrum surface• General drum wearPossible Consequences:• Rapid lining wear• If the wear pattern differs across theaxle, vehicle pull and excessivenoise can result6Deep irregularcircumferential groovesMain Reasons:• Large particles loose in the brake• Very poor drum condition andmaintenancePossible Consequences:• Very high lining and drum wear• Squeal3Scarred lining surfaceMain Reasons:• Poor drum condition,e.g. heat crazingPossible Consequences:• Rapid lining wear• If linings not 100% bedded-in, lowbrake efficiency can result7Lining surface taperedMain Reasons:• Brake shoes misaligned withthe brake drum• Distorted brake shoe or brake drumturned on taperPossible Consequences:• The linings may lock on tothe drum when braking fromhigh speeds• Vehicle pull and excessivebrake noise may occur