Before testing the brakes of a bus with hydraulic brakes and power assist, what should you do?

Pumping the brake pedal several times before testing the brakes of a bus with hydraulic brakes and power assist is essential for ensuring the system is functioning correctly and safely. This action helps to build up pressure in the brake lines and allows you to check if the power assist is operational. If the brakes are not functioning correctly, this step can help identify problems, such as whether the power assist is providing adequate support or if there might be air in the brake system.

Ensuring that the braking system is ready before taking further action is crucial in maintaining safety while operating the vehicle. Doing this step first allows for a smoother and safer brake test rather than assuming the brakes are functioning as they should be without verification.

On the other hand, using the parking brake is a good practice in general, but it is not the primary action needed specifically before testing hydraulic brakes with power assist. Turning off the ignition is also not necessary and could present risks, such as losing power to essential systems, which are critical for the test. Therefore, prioritizing the pumping of the brake pedal is vital for a practical and effective pre-test procedure.