ASE G1 Auto Maintenance and Light RepairBrakesEasy
A technician is performing a brake inspection on a vehicle equipped with drum brakes. They notice that the brake linings are severely worn, and the brake drum has deep grooves. The customer reports a grinding noise and reduced braking effectiveness. What is the MOST appropriate next step?
- ABleed the hydraulic system and inspect the wheel cylinders.
- BAdjust the parking brake cable and lubricate the backing plate.
- CResurface the brake drums and replace the brake shoes.
- DReplace the brake drums and brake shoes.
Show answer & explanationAnswer & explanation
Correct answer: D. Replace the brake drums and brake shoes.
Severely worn brake linings and deeply grooved drums indicate that both components are beyond their service limits and require replacement. Resurfacing drums with deep grooves is not advisable as it might exceed the minimum thickness specification or fail to remove all damage.
Why the other options are wrong
- A. Bleeding the hydraulic system or inspecting wheel cylinders addresses fluid-related issues, not mechanical wear of the shoes and drums.
- B. Adjusting the parking brake or lubricating the backing plate does not address the worn linings or grooved drums, which directly impact braking performance and noise.
- C. Resurfacing drums with deep grooves may exceed the maximum allowable diameter or minimum thickness, compromising safety and performance. Replacement is safer and more effective in this scenario.
Drum Brake Service
When drum brake linings and drums are severely worn or damaged, both components must be replaced to restore proper braking function.
- Check drum diameter against specification
- Replace shoes if worn or contaminated
- Replace drums if grooved or beyond service limit
Memory trick: Groovy drums and worn shoes mean a full replacement is due.