CDL Class A Practice Test

To verify that the trailer brakes operate correctly, it is essential to charge the air system and check the braking action. The air system must be adequately charged with air pressure to ensure the brake components work effectively. This involves checking that the air compressor reaches the required pressure before testing the brakes since proper air pressure is crucial for the brakes to function as designed.

After charging the system, you can perform a brake test by applying the brakes and monitoring their response. This step ensures that there are no leaks in the air system and that the trailer brakes engage and release properly. This systematic approach helps identify any issues with the braking system, which is vital for safety while operating a heavy vehicle.

Other options, while they may relate to certain aspects of brake function, do not provide a thorough assessment of the brakes' operational readiness. The process of charging the air system is an initial step that directly correlates with the effectiveness of the trailer brakes and should always be done before proceeding with a practical braking test.