Which parts comprise an air brake system on a CMV?

• A. Air compressor, reservoirs, protective devices, and air lines to brakes.
• B. Fuel injectors, spark plugs, battery.
• C. Radiator, hoses, thermostat.
• D. Steering linkage, power steering.

Answer: (A)

Air brakes on a CMV rely on a system that uses compressed air to apply and release the brakes. The essential parts are the air compressor that generates the air, the reservoirs that store it, protective devices that guard the system and regulate pressure, and the air lines that carry the compressed air to the brake actuators. Together, these components supply the necessary air pressure to operate the brakes and provide the ability to brake even if the engine isn’t running. The other options describe parts of the engine cooling system or the steering system, which are not part of the air brake setup.