ASE G1 Auto Maintenance and Light RepairBrakesEasy
After replacing the brake pads and rotors on a vehicle with front disc and rear drum brakes, the technician notices that the brake pedal feels lower than normal and requires more travel before the brakes engage effectively. What is the MOST likely cause of this condition?
- AOver-torqued lug nuts on the front wheels
- BAir trapped in the hydraulic system
- CA faulty brake booster
- DImproperly adjusted rear drum brakes
Show answer & explanationAnswer & explanation
Correct answer: D. Improperly adjusted rear drum brakes
After replacing front disc components, if the rear drum brakes are not properly adjusted, the shoes will have too much clearance from the drums, requiring the pedal to travel further to apply them, resulting in a low pedal.
Why the other options are wrong
- A. Over-torqued lug nuts can warp rotors or cause vibrations, but do not directly cause a low brake pedal feel or increased pedal travel.
- B. Air trapped in the system typically causes a spongy pedal, which is different from a low pedal that still feels firm once engaged.
- C. A faulty brake booster would cause a hard pedal, not a low pedal with increased travel.
Drum Brake Adjustment Post-Service
After brake service, especially when working on the front disc brakes, ensuring the rear drum brakes are properly adjusted is crucial. If the drum brakes are too loose, the pedal will feel low and have excessive travel before engaging.
- Drum brakes are self-adjusting but may need manual initial adjustment
- Excessive shoe-to-drum clearance causes low pedal
- Affects overall pedal feel and stopping effectiveness
Memory trick: Low Pedal, Long Travel, Drums Loose, No Gravel!