ASE G1 Auto Maintenance and Light RepairBrakesMedium
A technician is inspecting a vehicle's brake system. The customer reports a noticeable increase in stopping distance and a harder-than-normal brake pedal feel, especially during sudden stops. Upon inspection, the technician finds no external leaks in the hydraulic system and the brake pads and rotors are within specification. Which of the following is the MOST likely cause of these symptoms?
- AContaminated brake fluid
- BWorn brake pads requiring replacement
- CAn improperly adjusted parking brake
- DA malfunctioning brake booster
Show answer & explanationAnswer & explanation
Correct answer: D. A malfunctioning brake booster
A malfunctioning brake booster reduces the power assist to the brake pedal, requiring more effort from the driver to achieve the same stopping force, thus increasing stopping distance and making the pedal feel harder.
Why the other options are wrong
- A. Contaminated brake fluid usually causes a spongy or low pedal, or can lead to internal component damage, not a hard pedal.
- B. Worn brake pads would typically cause a soft pedal, grinding, or squealing, not a hard pedal and increased stopping distance without other issues.
- C. An improperly adjusted parking brake primarily affects parking brake function and could cause drag, but typically not a hard service brake pedal or increased stopping distance during normal braking.
Brake Booster Malfunction
A failure in the brake booster system, which is designed to multiply the force applied to the brake pedal, resulting in a significantly harder pedal feel and increased stopping distances.
- Vacuum or hydraulic assist mechanism
- Reduces driver effort for braking
- Malfunction leads to hard pedal and poor stopping
Memory trick: Hard Pedal, Slow Stop: Boost Gone!