User's Manual
13
BRAKE SYSTEMS DIAGNOSTIC GUIDE
POTENTIAL CONDITION/CAUSE ACTION (SERVICE MANUAL SECTION)
Blockage in air lines preventing air chamber from exhausting:
• Air line inner lining separation Replace line
• Plugged lines Remove blockage
• Contamination Remove contamination
• Damaged fittings Replace fittings
Air valves sticking:
• Seals/O-rings damaged Replace seals/O-rings
• External vents blocked Remove blockage
• Contamination Remove contamination
• Worn valves/internal component failures Repair or replace as required
Spring brake not functioning:
• Power spring failure Replace spring brake chamber
Air chamber not set properly:
• Too much rod free-travel Adjust brakes (2)
• Air chamber in wrong position in bracket slot Reposition air chamber or bracket (3
• Pushrod length too long Adjust clevis or shorten pushrod (2)
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 (Eaton-Haldex) Perform correct setup procedure (2)
• Broken or bent parts Replace damaged parts as required (3,6)
No force at shoes:
• Grease, oil or dirt on linings Replace linings (5)
Lack of friction:
• Glazed linings Deglaze or replace linings (5)
• Worn/damaged drums Replace drums (3)
• New linings, not burnished Burnish linings
PARKING BRAKE WILL NOT HOLD/
DRAGGING BRAKES