Noise, Brake systems diagnostic guide – Bendix Commercial Vehicle Systems BRAKE SYSTEM TROUBLESHOOTING GUIDE User Manual

Page 9

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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

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