If a vehicle is equipped with a vacuum brake system, what must be done for the pedal test?

For a vehicle equipped with a vacuum brake system, building vacuum before applying the brakes is essential to ensure they operate correctly. The process of allowing the vacuum to build for one minute before application ensures that the brake assist mechanism is fully operational, providing sufficient force to the brake system. Without adequate vacuum, the brake system may not function effectively, leading to inadequate braking force or a potential brake failure during testing.

Building the vacuum promotes safety and reliability during the brake system evaluation. It allows the driver to experience the full benefit of the vacuum assist feature, ensuring that the brakes respond as intended when applied. This step also helps identify any issues with the vacuum system that could affect braking performance.

In contrast, the other options do not align with the proper testing protocol for a vacuum brake system, as they do not adequately prepare the system for an accurate assessment of its performance.