Michigan State Brakes Certification Practice Exam

When a vacuum diaphragm in a brake power booster is cracked or torn, it compromises the booster’s ability to assist the driver in applying the brakes. The power booster relies on vacuum pressure to amplify the force exerted by the brake pedal. With a damaged diaphragm, this vacuum pressure cannot be maintained properly, leading to a situation where the brake booster is effectively bypassed.

As a result, the driver will experience a hard pedal feel that requires significantly more effort to apply the brakes. This is because without the assistance from the vacuum booster, the driver has to exert their own strength to engage the braking system fully. The sensation of a hard brake pedal is a direct consequence of losing the enhanced braking force that the booster normally provides when operating correctly.

Understanding this mechanism is crucial for diagnosing brake issues accurately since it highlights the importance of the vacuum booster in the overall braking system performance.