Brake System Diagnosis Excessive Brake Pedal Travel
Causes | Correction |
|---|---|
Air in the brake system | Bleed the brake system. |
Improper rear brake adjustment | Adjust the rear brake linings. |
Leaking brake pipe or connection | Locate and repair the brake pipe or the connection. |
Leaking caliper piston seal | Replace the caliper piston seal. |
Leaking master cylinder (internally) | Repair or replace the master cylinder. |
Contaminated/improper brake fluid | Flush the brake system and repair the affected brake components. |
Uneven lining material | Replace the linings as an axle set. |
Loose front or rear brake assembly attachment | Locate and tighten loose brake components. |
Excessive vehicle loading | Refer to tire placard for the vehicle capacity specification. |
Brake System Diagnosis Pedal Travel Increases
Causes | Correction |
|---|---|
DEFINITION: Brake Pedal Travel Gradually Increases | |
Leaking brake pipe or connection | Locate and repair the brake pipe or the connection. |
Leaking caliper piston seal | Replace caliper piston seal. |
Leaking master cylinder (internally) | Repair or replace the master cylinder. |
Restricted passage in the vacuum booster | Replace the vacuum booster. |
Damaged vacuum booster | Replace the vacuum booster. |
Restricted brake fluid passage | Locate and repair the brake fluid passage restriction. |
Improper rear brake adjustment | Adjust the rear brake linings. |
Brake System Diagnosis Too Much Pedal Effort Required
Causes | Correction |
|---|---|
DEFINITION: Excessive Brake Pedal Effort | |
Glazed brake linings | Replace the brake linings. |
Leaking vacuum booster | Replace the vacuum booster. |
Restricted passage in the vacuum booster | Locate and fix the source of the vacuum restriction in the vacuum booster. |
Damaged vacuum booster | Replace the vacuum booster. |
Worn out brake linings | Replace the brake linings. |
Incorrect lining material | Replace the brake linings. |
Contaminated brake linings | Replace the brake linings. |
Linings damaged by abusive use | Replace the brake linings. |
Restricted brake fluid passage | Locate and repair the brake fluid passage restriction. |
Brake pedal linkage interference or binding | Repair or replace the brake pedal linkage. |
Operator riding the brake pedal | Advise the operator of proper brake usage. |
Low engine vacuum | Diagnose the low engine vacuum condition. |
Excessive vehicle loading | Refer to the tire placard for the vehicle capacity specification. |
Brake System Diagnosis Excessive Brake Action
Causes | Correction |
|---|---|
Linings damaged by abusive use | Replace the brake linings. |
Damaged vacuum booster | Replace the vacuum booster. |
Worn out brake linings | Replace the brake linings. |
Uneven brake lining wear | Replace the brake linings. |
Incorrect lining material | Replace the brake linings. |
Improper rotor surface finish | Refinish the rotor surface or replace the rotor. |
Scored rotor | Refinish the rotor surface or replace the rotor. |
Improper thickness variation in the rotor | Repair or replace the rotor. |
Excessive rotor lateral runout | Repair or replace the rotor. |
Loose front or rear brake assembly attachment | Locate and tighten the loose brake components. |
Brake System Diagnosis Brakes Slow to Respond
Causes | Correction |
|---|---|
Restricted passage in vacuum booster | Replace the vacuum booster. |
Contaminated/improper brake fluid | Flush the brake system and repair the affected brake components. |
Leaking vacuum booster | Replace the vacuum booster |
Damaged vacuum booster | Replace the vacuum booster |
Glazed brake linings | Replace the glazed brake linings. |
Restricted brake fluid passage | Locate and repair the source of the brake fluid restriction. |
Brake pedal linkage interference/binding | Repair or replace the brake pedal linkage. |
Sticky caliper or caliper pistons | Replace or repair the caliper. |
Low engine vacuum | Diagnose the low engine vacuum condition. |
Brake System Diagnosis Brakes Slow to Release
Causes | Correction |
|---|---|
Damaged vacuum booster | Replace the vacuum booster |
Brake pedal linkage interference/binding | Repair or replace the brake pedal linkage. |
Contaminated or improper brake fluid | Flush the brake system and repair the affected brake components. |
Restricted passage in the vacuum booster | Locate and repair the restriction in the vacuum booster. |
Restricted brake fluid passage | Locate and repair the brake fluid restriction. |
Sticky caliper or caliper pistons | Replace or repair the caliper. |
Parking brake not releasing | Repair the malfunctioning parking brake lever or the frozen parking brake cables. |
Improper caliper to knuckle clearance | Repair as necessary. |
Brake System Diagnosis Brakes Drag
Causes | Correction |
|---|---|
Sticky caliper or caliper pistons | Repair or replace the caliper. |
Contaminated or improper brake fluid | Flush the brake system and repair the affected brake components. |
Uneven brake lining material | Replace the brake linings. |
Loose front or rear brake assembly attachment | Locate and tighten the loose brake components. |
Restricted brake fluid passage | Locate and repair the source of the brake fluid restriction. |
Improperly adjusted stoplamp switch | Adjust the stoplamp switch to specification. |
Brake pedal linkage interference/binding | Repair or replace the brake pedal linkage. |
Improperly adjusted parking brake | Adjust the parking brake. |
Loose front suspension parts | Locate and tighten, repair or replace the loose front suspension components. |
Operator riding brake pedal | Advise the operator of the proper brake usage. |
Brake System Diagnosis Uneven Action (Side to Side)
Causes | Correction |
|---|---|
Incorrect front wheel alignment | Set the front end alignment to specification. |
Contaminated brake linings | Replace the brake linings. |
Incorrect tire pressure | Set the tire pressure to specification. |
Loose front suspension parts | Locate and tighten, repair or replace the loose front suspension components. |
Contaminated or improper brake fluid | Flush the brake system and repair the affected brake components. |
Worn out brake linings | Replace the brake linings. |
Uneven brake lining material | Replace the brake linings. |
Glazed brake linings | Replace the brake linings. |
Incorrect lining material | Replace the brake linings. |
Lining damaged by abusive use | Replace the brake linings. |
Scored rotor | Refinish the rotor surface or replace the rotor. |
Loose front or rear brake assembly attachment | Locate and tighten the loose brake components. |
Restricted brake fluid passage | Locate and repair the source of the brake fluid restriction. |
Sticky caliper or caliper pistons | Repair or replace the caliper. |
Parking brake not releasing | Repair the malfunctioning park brake lever or frozen parking brake cables. |
Improper caliper to knuckle clearance | Repair as necessary. |
Brake System Diagnosis Uneven Action (Front to Rear)
Causes | Correction |
|---|---|
Contaminated brake linings | Replace the brake linings. |
Excessive vehicle loading | Refer to the tire placard for the vehicle capacity specification. |
Leaking brake pipe or connection | Locate and repair the brake pipe or the connection. |
Leaking caliper piston seal | Repair or replace the caliper. |
Leaking master cylinder (internally) | Repair or replace the master cylinder. |
Air in the brake system | Bleed the brake system. |
Contaminated or improper brake fluid | Flush the brake system and repair the affected brake components. |
Worn out brake linings | Replace the brake linings. |
Uneven brake lining material | Replace the brake linings. |
Glazed brake linings | Replace the brake linings. |
Incorrect lining material | Replace the brake linings. |
Linings damaged by abusive use | Replace the brake linings. |
Scored rotor | Refinish the rotor surface or replace the rotor. |
Loose front or rear brake assembly | Locate and tighten loose brake components. |
Restricted brake fluid passage | Locate and repair the source of the brake fluid restriction. |
Improperly adjusted parking brake | Adjust the parking brake. |
Sticky caliper or caliper pistons | Repair or replace the caliper. |
Improper rear brake adjustment | Adjust the rear brake linings. |
Brake System Diagnosis Scraping Noise From Brakes
Causes | Correction |
|---|---|
Loose front suspension parts | Locate and tighten, repair or replace the loose front suspension components. |
Worn out brake linings | Replace the brake linings. |
Uneven brake lining material | Replace the brake linings. |
Contaminated brake linings | Replace the brake linings. |
Linings damaged by abusive use | Replace the brake linings. |
Front or rear brake assembly attachment loose | Locate and tighten the loose brake components. |
Brake System Diagnosis Squeak Without Application
Causes | Correction |
|---|---|
Worn out brake linings | Replace the brake linings. |
Uneven brake lining material | Replace the brake linings. |
Incorrect lining material | Replace the brake linings. |
Contaminated brake linings | Replace the brake linings. |
Linings damaged by abusive use | Replace the brake linings. |
Scored rotor | Refinish the rotor surface or replace the rotor. |
Brake System Diagnosis Squeak During Stop
Causes | Correction |
|---|---|
Loose front suspension parts | Locate and tighten, repair or replace the loose front suspension components. |
Worn out brake linings | Replace the brake linings. |
Uneven brake lining material | Replace the brake linings. |
Contaminated brake linings | Replace the brake linings. |
Linings damaged by abusive use | Replace the brake linings. |
Brake System Diagnosis Brake Chatter/Roughness
Causes | Correction |
|---|---|
Scored rotor | Refinish rotor surface or replace the rotor. |
Improper thickness variation in rotor | Repair or replace the rotor. |
Out-of-balance tire and wheel assembly or assemblies | Locate and repair out-of-balance tire and wheel assembly or assemblies |
Excessive rotor lateral runout | Repair or replace the rotor. |
Loose front or rear brake assembly attachment | Locate and tighten the loose brake components. |
Loose front suspension parts | Locate and tighten, repair, or replace the loose front suspension components. |
Incorrect wheel nut torque | Tighten the wheel nuts to specification. |
Poor drum surface finish | Refinish the drum surface or replace drum. |
Brake System Diagnosis Brakes Groan at End of Stop
Cause | Correction |
|---|---|
Linings damaged by abusive use | Replace the brake linings. |
Poor drum surface finish | Refinish the drum or replace the drum. |
Poor rotor surface finish | Refinish the rotor or replace the rotor. |
Brake System Diagnosis Brake Indicator On
Causes | Correction |
|---|---|
Air in the brake system | Bleed the brake system |
Leaking brake pipe or connection | Locate and repair the brake pipe or the connection. |
Parking brake switch circuit grounded | Locate and repair the short to the ground in the parking brake switch circuit. |
Parking brake not released | Release the parking brake lever. |
Low brake fluid | Add brake fluid to the master cylinder reservoir |
Leaking caliper piston seal | Replace the caliper piston seal. |
Leaking master cylinder (internally) | Repair or replace the master cylinder. |
Uneven brake linings | Replace the brake linings. |
Brake System Diagnosis Premature Lining Wear-Out
Causes | Correction |
|---|---|
Leaking brake pipe or connection | Locate and repair brake pipe or the connection. |
Improperly adjusted stoplamp switch | Adjust the stoplamp switch to specification. |
Brake pedal linkage interference or binding | Repair or replace the brake pedal linkage. |
Out-of-balance tire and wheel assembly or assemblies | Locate and repair out-of-balance tire and wheel assembly or assemblies. |
Operator riding on brake pedal | Advise the operator of proper brake usage. |
Improper caliper to knuckle clearance | Repair as necessary. |
Brake System Diagnosis Parking Brake Will Not Hold
Causes | Correction |
|---|---|
Improperly adjusted parking brake | Adjust the parking brake. |
Brake System Diagnosis Parking Brake Will Not Release
Causes | Correction |
|---|---|
Parking brake cables frozen | Replace the parking brake cables. |
Parking brake cables corroded | Replace the parking brake cables. |
Brake System Diagnosis Brake Pulsation
Causes | Correction |
|---|---|
Improper thickness variation in the rotor | Repair or replace the rotor. |
Scored rotor | Refinish the rotor surface or replace the rotor. |
Excessive rotor lateral runout | Repair or replace the rotor. |
Out-of-balance tire/wheel assembly or assemblies | Locate and repair out-of-balance tire and wheel assembly or assemblies. |
Improper wheel nuts torque | Tighten the wheel nuts to specification. |
Poor drum surface finish | Refinish the drum surface or replace the drum. |
Brake System Diagnosis Brake Pulls
Causes | Correction |
|---|---|
Leaking brake pipe or connection | Locate and repair the brake pipe or the connection. |
Leaking piston seal | Replace the caliper piston seal. |
Uneven brake lining material | Replace the brake linings. |
Incorrect lining material | Replace the brake linings. |
Contaminated brake linings | Replace the brake linings. |
Linings damaged by abusive use | Replace the brake linings. |
Improper rotor surface finish | Refinish the rotor surface or replace the rotor. |
Incorrect front wheel alignment | Set the front end alignment to specification. |
Incorrect tire pressure | Set the tire pressure to specifications. |
Loose front suspension parts | Locate and tighten, repair or replace the loose front suspension components. |
Improper caliper to knuckle clearance | Repair as necessary. |
