Drum Brake System: Testing and Inspection

Rear Drum Brake Inspection

CAUTION: Frequent inhalation of brake pad dust, regardless of material composition, could be hazardous to your health. Avoid breathing dust particles. Never use an air hose or brush to clean brake assemblies. Use an OSHA-approved vacuum cleaner.

NOTICE: To avoid damage, do not strike aluminum parts with a metal hammer. If necessary, tap gently with a plastic tipped hammer.

1. Raise the rear of the vehicle, and support it with safety stands in the proper location. Remove the rear fender skirts, and rear wheels.





2. Release the parking brake, and remove the brake drum.





3. Check the wheel cylinder (A) for leakage.
4. Check the brake linings (B) for cracking, glazing, wear, and contamination.
5. Measure the brake lining thickness (C). Measurement does not include brake shoe thickness.
Brake lining thickness
Standard: 4.3 mm (0.17 inch)
Service limit: 1.0 mm (0.04 inch)
6. If the brake lining thickness is less than the service limit, replace the brake shoes as a set.
7. Check the hub bearing for smooth operation. If it requires servicing, replace it.





8. Measure the inside diameter of the brake drum with inside vernier calipers.
Drum inside diameter
Standard: 179.9 - 180.0 mm (7.083 - 7.087 inch)
Service limit: 181.0 mm (7.126 inch)
9. If the inside diameter of the brake drum is beyond the service limit, replace the brake drum.
10. Check the brake drum for scoring, grooves, cracks, and corrosion.