User's Manual

BRAKE SYSTEMS DIAGNOSTIC GUIDE

POTENTIAL CONDITION/CAUSE ACTION (SERVICE MANUAL SECTION)

Dragging brakes See DRAGGING BRAKES

Poor lining-to-drum contact. Linings are tapered

across width:

• Bell-mouthed drum  Replace drum (3)

• Bent brake spider  Replace spider (3,6)

• Bent or stretched brake shoe  Replace shoe (3,6)

• Loose wheel bearing  Torque spindle nuts and check end play (6)

• Worn or damaged cam  Replace cam (3,6)

Shoe-to-shoe variation:

• Mismatched lining friction codes  Replace lining(s) with proper friction code (5)

• Stretched shoe  Replace shoe (3,6)

Brake components:

• Flat spots on cam or roller  Replace cam or roller (3,6)

• Worn anchor pin  Replace anchor pin (3,6)

• Worn camshaft or bushings  Replace camshaft and bushings (5)

Unequal wear on side-to-side brakes for same axle:

• Mismatched lining friction codes  Replace lining(s) with proper friction code (5)

• Seized or binding camshaft  Clean and lubricate camshaft (2)

• Brake drum surface in poor condition  Replace drum (3)

• Loose wheel bearing  Torque spindle nuts and check end play (6)

• Performing downgrade braking using light drag  Use snub method on downgrades

Slack adjuster not set properly:

• Incorrect installation of slack adjuster  Install slack adjuster properly (3,6)

• Incorrect in-service adjustment  Check and correct adjustment procedure (2)

• Incorrect setup of external reference control arms  Perform correct setup procedure (2)

(Eaton-Haldex)

• Broken or bent parts  Replace damaged parts as required (3,6)

Wear on edge of lining:

• Wrong lining width  Replace lining (5)

• Wrong drum  Replace drum (3)

• Loose bearing adjustment. Bearing spacer missing or too thin  Replace spacer and torque spindle nuts. Check end

play (6)

PREMATURE LINING WEAR