User's Manual

BRAKE SYSTEMS DIAGNOSTIC GUIDE

POTENTIAL CONDITION/CAUSE ACTION (SERVICE MANUAL SECTION)

Contamination -

—No air dryer  Install air dryer

—Faulty air dryer  Repair or replace

—Dirty or damaged filter  Replace filter

—Desiccant debris  Clean desiccant

—Incompatible oils  Drain and refill with proper oil

—Leaking air tanks  Repair or replace tank

—Mis-adjusted brakes  Readjust brakes

Insufficient pushrod free travel:

• Pushrod length too long  Shorten pushrod to proper length

• Incorrect installation of slack adjuster  Perform correct installation procedure (6)

Overadjusted slack adjuster:

• Incorrect in-service adjustment (manual)  Readjust using proper procedure

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

(Eaton-Haldex)

• Incorrect slack window (auto slacks)  Replace with proper slack window (6)

• Contamination of internal parts (auto)  Replace slack adjuster (6)

• False feedback to slack adjuster (review all  Check lining clearances and hub/drum run-out (4)

foundation brake and wheel end problems)

• Auto slack installed and/or adjusted with spring  Readjust with spring brake fully retracted

brake partially applied (low reservoir pressure)

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

Cam flip over:

• Worn linings/drums  Replace linings/drums (3,5,6)

• Worn shoes/rollers  Replace as necessary (3,6)

• Worn cam  Replace cam (3,6)

Binding of camshaft in bushings:

• Corrosion  Replace bushings and lubricate (5)

• Lack of lubricant  Lubricate with proper lubricant (2)

• Damaged bushings/journals  Replace bushings/journals (5)

Drum out-of-round:

• Worn-out drum  Replace drum (3,6)

• Overloading of vehicle  Don’t exceed legal weight rating of vehicle

• Over-aggressive linings  Change lining friction rating

• Driver abuse  Correct as required

• Incorrect turning of drum  Perform correct drum turning operation (2)

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

PARKING BRAKE WILL NOT HOLD/

DRAGGING BRAKES