The owner of a vehicle complains the car is hard to stop. The technician doing the diagnosis starts by pumping the brake pedal several times with the engine off, and then starts the engine while holding firm pressure on the brake pedal. The pedal falls away slightly and less pressure is needed to maintain the pedal in any position. This test proves that ______.

Question

Quizplus · Accepted Answer

The test described is used to check the functionality of the vacuum booster. When the engine starts, vacuum is applied to the booster, which should cause the brake pedal to fall slightly if the booster is working properly.

The Owner of a Vehicle Complains the Car Is Hard