Drum Brake System Testing
WARNING: This page is about a different car, the 2002 Pontiac Montana, 2002 Oldsmobile Silhouette, and 2002 Chevrolet Venture. However, it is still accessible from the selected car via links, so may be relevant.
- Were you sent here from General Diagnosis? If so, go to next step. If not, go to DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKE under TROUBLE SHOOTING.
- Remove the brake drums. Inspect the drum brake shoes for the following conditions:
- Uneven and/or abnormal wear, edge-to-edge and/or side-to-side
- Contamination from an external substance
- Looseness, damage, glazing, or incorrect lining material
- Are any of the brake shoes contaminated? If so, go to next step. If not, go to step 5 .
- Inspect the wheel cylinders for evidence of an external brake fluid leak. Replace any wheel cylinder that is found to be leaking brake fluid. See WHEEL CYLINDER under REMOVAL & INSTALLATION. Did you complete the inspection and replacement? If so, go to step 6 .
- Inspect the drum brake hardware for any components which are worn, damaged, discolored due to stress, broken or missing. See DRUM BRAKE ADJUSTING HARDWARE INSPECTION under ADJUSTMENTS & INSPECTIONS. Replace components as required. See DRUM BRAKE HARDWARE under REMOVAL & INSTALLATION. Replace the drum brake shoes. See BRAKE SHOES under REMOVAL & INSTALLATION. Did you complete the inspection and replacement? If so, go to step 8 .
- Clean the remaining drum brake system components to remove any traces of the contaminant. Inspect the drum brake hardware for any components which are worn, damaged, discolored due to stress, broken or missing. See BRAKE DRUM HARDWARE INSPECTION under ADJUSTMENTS & INSPECTIONS. Replace the drum brake hardware components as required. See DRUM BRAKE HARDWARE under REMOVAL & INSTALLATION. Replace the contaminated brake shoes. See BRAKE SHOES under REMOVAL & INSTALLATION. Did you complete the cleaning, inspection and replacement? If so, go to step 8 .
- Inspect the drum brake hardware for any components which are worn, damaged, discolored due to stress, broken or missing. Did you complete the inspection and, if necessary, the replacement? If so, go to next step.
- Check the diameter of each of the brake drums. Make a determination for each brake drum if the drum can be REFINISHED and REMAIN ABOVE the minimum requirements. See BRAKE DRUM DIAMETER MEASUREMENT under ADJUSTMENT & INSPECTIONS. Does the brake drum meet the minimum requirements for REFINISHING? If so, go to next step. If not, go to step 11 .
- Inspect each of the brake drums for the following surface and wear conditions:
Braking Surface Conditions
- Heavy rust and/or pitting.
- Cracks and/or heat spots.
- Excessive blueing discoloration and missing balance weights.
Braking Surface Wear Conditions
- Deep or excessive scoring beyond maximum acceptable level.
- Radial runout beyond maximum acceptable level.
- Drum exhibits one or more of the Braking Surface Conditions listed previously.
- Drum is beyond the acceptable level in one or more of the Braking Surface Wear Conditions listed previously.
- Refinish the brake drum. See DRUM BRAKE REFINISHING under ADJUSTMENTS & INSPECTIONS. Inspect the brake drum diameter. See BRAKE DRUM DIAMETER MEASUREMENT under ADJUSTMENTS & INSPECTIONS. Were you able to REFINISH the brake drum within the minimum requirements? If so, go to step 14 . If not, go to step 13 .
- Is the brake drum at or below the DISCARD requirements? If so, go to step 13 . If not, go to next step.
- Inspect each of the brake drums for the following surface and wear conditions:
Braking Surface Conditions
- Heavy rust and/or pitting.
- Cracks and/or heat spots.
- Excessive blueing discoloration or missing balance weights.
Braking Surface Wear Conditions
- Deep or excessive scoring beyond maximum acceptable level.
- Radial runout beyond maximum acceptable level.
- Drum exhibits one or more of the Braking Surface Conditions listed previously.
- Drum is beyond the acceptable level in one or more of the Braking Surface Wear Conditions listed previously.
- Replace the brake drum. After repairs are complete, go to next step.
- Inspect the brake shoes for proper adjustment. See DRUM BRAKE ADJUSTMENT under ADJUSTMENTS & INSPECTIONS. Are the brake shoes adjusted properly? If so, go to step 18 . If not, go to next step.
- Inspect the components of the brake drum adjustment hardware system for free movement and correct operation. See DRUM BRAKE ADJUSTING HARDWARE INSPECTION under ADJUSTMENTS & INSPECTIONS. Do the drum brake adjusting hardware components operate freely and correctly? If so, go to step 17 . If not, go to next step.
- Replace the drum brake adjusting hardware components as necessary. See DRUM BRAKE ADJUSTING HARDWARE under REMOVAL & INSTALLATION. Is the replacement complete? If so, go to next step.
- Adjust the drum brake shoes. See DRUM BRAKE ADJUSTMENT under ADJUSTMENTS & INSPECTIONS. Were you able to complete the adjustment? If so, go to step 20 . If not, go to SYMPTOMS - HYDRAULIC BRAKE under TROUBLE SHOOTING.
- Inspect the drum brake backing plate for the following:
- Excessive wear or rust.
- Damage and/or evidence of contact with the brake drum.
- Repair or replace the drum brake backing plate as necessary. See DRUM BRAKE BACKING PLATE under REMOVAL & INSTALLATION. After repairs are complete, go to next step.
- Install or connect components that were removed or disconnected during diagnosis. Did you complete the operation? If so, system is okay. If system is not okay, go to step 2 .