CATBE501

Brake Lining FaultsUneven lining surface8 12Main Reasons:• Wrongly adjusted or wornaxle bearingsPossible Consequences:• Very high lining and drum wear• SquealDirt on the lining surfaceMain Reasons:• Dirt particles in the brake• Poor brake maintenance(insufficient cleaning)Possible Consequences:• High lining and drum wear• Poor deceleration• Vehicle pull and excessive brakenoise may occur9Cracks around rivet holesMain Reasons:• Too heavy riveting force• Wrong shape of rivet heads• Brake shoe radius does notconform to lining radius• Brake shoe platform is notclean or evenPossible Consequences:• Lining and drum breakage• Brake over-heating• Noise13Build up of dirt betweenlining and brake shoeMain Reasons:• Shoe radius out of line• Shoe platform not blast cleaned andpainted properly• Shoe platform not parallel• Lining riveted incorrectlyPossible Consequences:• Cracks in the lining material or crackin drum surface• Loose linings• Squeal• Improper cleaning causes rust scaleto build up and lift the lining from theshoe1011Greasy lining surfaceSurface crazingMain Reasons:• Broken or improperly mounted huboil seals• Excessive lubrication of the bearingsof the braking mechanismPossible Consequences:• Vehicle pull may occur if theproblem is only found at one side ofthe axle• Low decelerationMain Reasons:• Caused by excessive braketemperature, i.e. when brake is coldon motorway then having to performa sudden stop i.e. off a slip road.Rapid temperature input does notallow for heat soak frommaterial into brake systemPossible Consequences:• This condition has no effect on theintegrity or performance of the lining• Penetration of the crazing is usuallyno more than 1mm deep• Wear through with normal brakeuse and has no effect on the lining1415Large fractures in lining surfaceMain Reasons:• Faults in brake mechanism• Sticking brake shoes (weak returnsprings)• Excessive use of brakes at highspeed• Overloaded vehicle• Too large air chambersBurnt lining surfacePossible Consequences:• High lining wear• Vehicle pull and excessive brake noise• Disintegration of lining• Low decelerationMain Reasons:• Faults in brake mechanism• Sticking brake shoes (weakreturn springs)• Excessive use of brakes fromhigh speed• Wrong brake cylinders/air chambersor levers• Overloaded vehicle• Incorrect brake proportioningbetween tractor/trailer unitsPossible Consequences:• High lining wear• Vehicle pull and excessive brake noise• Deceleration too low