User's Manual
7
BRAKE SYSTEMS DIAGNOSTIC GUIDE
POTENTIAL CONDITION/CAUSE ACTION (SERVICE MANUAL SECTION)
Dragging brakes See DRAGGING BRAKES
Insufficient lining-to-drum contact:
• Bell-mouthed drum condition Replace drum (3,6)
• Poor surface condition of drum Rebore or replace drum (3,6)
• 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 camshaft Replace camshaft (3,6)
• Improper lining grind Grind linings to fit drum radius
Linings tapered across width:
• Bell-mouthed drum condition Replace drum (3,6)
• Poor surface condition of drum Rebore or replace drum (3,6)
• Bent brake spider Replace spider (3,6)
• Loose wheel bearing Torque spindle nuts and check end play (6)
Unequal shoe wear on same brake:
• Mismatched lining friction codes Correct as required with proper lining (5)
• Worn camshaft or bushings Replace camshaft or bushings (3,6)
Glazed linings:
• Unbalanced brake system Inspect brake system (2)
• Incorrect lining for vehicle type and service Install proper lining (6)
• Dragging spring brake chamber Inspect valves and chamber for leaks. Replace air
chamber (4,6)
Scored or grooved linings and drum:
• Improperly machined drum Replace or machine drum (3,6)
• Abrasive material between lining and drum Remove dirt and debris. Clean drum and remachine
if required (3)
Loose lining:
• Improper rivet size Replace rivets (5)
• Improper crimping of rivets Replace rivets (5)
• Enlarged rivet holes in shoe Replace shoe (3,6)
• Incorrect lining hole size or counterbore depth Replace lining (5)
Cracked lining at rivet holes:
• Dirt or rust on shoe table Remove dirt and debris. Clean and repaint shoe (3)
• Incorrect counterbore lining size Replace linings (5)
• Loose rivets Replace linings and check rivet process (5)
NOISE