Drum Brake System Testing

WARNING: This page is about a different car, the 2002 GMC Savana Special, 2002 GMC Savana Camper Special, 2002 GMC Savana, and 2002 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.

Were you sent here from DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES? If so, go to next step. If not, see DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES .
Remove the brake drums. See REAR BRAKE DRUM . Inspect the drum brake shoes for the following conditions:
- Lining thickness below specifications.
- 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.
Did you find any conditions to indicate a concern with any of the drum brake shoes? If so, go to next step. If not, go to step 7 .
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 . After repairs are complete, 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 HARDWARE INSPECTION . Replace the drum brake shoes. See REAR BRAKE SHOES . After repairs are complete, 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 DRUM BRAKE HARDWARE INSPECTION . Replace the drum brake hardware components as required. See DRUM BRAKE HARDWARE . Replace the contaminated brake shoes. See REAR BRAKE SHOES . After repairs are complete, go to step 8 .
Inspect the drum brake hardware for any components which are worn, damaged, discolored due to stress, broken or missing. See DRUM BRAKE HARDWARE INSPECTION . Replace components as required. See under DRUM BRAKE HARDWARE . After repairs are complete, 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 DRUM BRAKE DIAMETER MEASUREMENT . 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.
- Missing balance weights.
Braking Surface Wear Conditions
- Deep or excessive scoring beyond maximum acceptable level.
- Radial runout beyond maximum acceptable level.
Make a determination for each brake drum if the drum requires refinishing based upon the results of the inspection. If the brake drum exhibits any of the following conditions, it requires refinishing.
- 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.
Does the brake drum require refinishing? If so, go to next step. If not, go to step 14 .
Refinish the brake drum. See DRUM BRAKE REFINISHING . Inspect the brake drum diameter. See BRAKE DRUM DIAMETER MEASUREMENT . 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.
- Missing balance weights.
Braking Surface Wear Conditions
- Deep or excessive scoring beyond maximum acceptable level.
- Radial runout beyond maximum acceptable level.
Make a determination for each brake drum if the drum requires replacement based upon the results of the inspection. If a brake drum exhibits any of the following conditions, it requires replacement.
- 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.
Does the brake drum require replacement? If so, go to next step. If not, go to step 14 .
Replace the brake drum. See REAR BRAKE DRUM . After repairs are complete, go to next step.
Inspect the brake shoes for proper adjustment. See DRUM BRAKE ADJUSTMENT . 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 . 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 HARDWARE . After repairs are complete, go to next step.
Adjust the drum brake shoes. See DRUM BRAKE ADJUSTMENT . After repairs are complete, go to step 20 .
Inspect the drum brake backing plate for the following:
- Excessive wear or rust.
- Damage and/or evidence of contact with the brake drum.
Does the drum brake backing plate exhibit any of these conditions? If so, go to next step. If not, go to step 20 .
Repair or replace the drum brake backing plate as necessary. See DRUM BRAKE BACKING PLATE . After repairs are complete, go to next step.
Install or connect components that were removed or disconnected during diagnosis. If condition is still present, go to step 2 . If condition is corrected, then system is okay.