Air Brake Practice Test 2026 – All-in-One Resource to Master Your Certification!

The reservoir is the part of the air brake system that holds air pressure. In an air brake system, the reservoir stores compressed air that is generated by the compressor. This stored air is essential for the operation of the brake system, as it provides the power necessary to engage the brakes when the driver applies pressure to the brake pedal. The design of the system ensures that there is always a supply of air ready to be used, which is crucial for maintaining consistent braking performance.

Other components serve different functions; for example, the compressor is responsible for generating the compressed air but does not store it. The brake pedal is the control interface that the driver uses to apply the brakes, and the warning light indicates issues within the system but does not hold air pressure itself. Hence, the reservoir is the critical component that specifically holds and manages the air pressure required for effective braking.