Michigan State Brakes Certification Practice Exam 2026 - Free Brakes Certification Practice Questions and Study Guide

To test a vacuum power brake booster, pumping the brake pedal at least four times while the engine is off is the appropriate action. This process helps to deplete the vacuum stored in the booster, allowing for the evaluation of its effectiveness once the engine is started.

When you pump the brake pedal, you consistently engage the brake booster mechanism, which ensures that any residual vacuum is used up. After this action, when the engine is started, you can then observe how the brake pedal responds. If the booster is functioning properly, you should feel a noticeable change in pedal firmness, indicating that the booster is successfully assisting the braking effort.

The other options do not effectively evaluate the booster’s functionality. Maintaining pressure on the pedal while the engine is off does not test how the system operates once the engine is running. Rapidly depressing and releasing the pedal or holding it for an extended period does not provide the same clear indication of the booster’s operational readiness once the engine starts. Thus, pumping the brake pedal at least four times is a critical step to ensure an accurate assessment of the vacuum power brake booster.