What is an air-actuated braking system?

What is an air-actuated braking system?

• A. A braking system that uses compressed air to hold off the spring brake and applies air pressure to a service brake for stopping.
• B. A system that uses hydraulic fluid to pressurize brakes.
• C. A mechanical linkage brake system.
• D. A system that uses electric motor-assisted braking.

Answer: (A)

Air-actuated braking systems use compressed air to do the braking work. The driver’s braking action sends air pressure to the brake chambers, which pushes pistons to apply the service brakes and slow the vehicle. At the same time, the system keeps a spring brake held off by that air pressure; the spring brake acts as a fail-safe parking/emergency brake. If air pressure is lost, the spring brake automatically applies, bringing the vehicle to a stop. So this type of system relies on air pressure both to release the parking brake and to actuate the service brakes for stopping. The other options describe hydraulic, mechanical, or electric braking approaches, which are not air-actuated.

Air-actuated braking systems use compressed air to do the braking work. The driver’s braking action sends air pressure to the brake chambers, which pushes pistons to apply the service brakes and slow the vehicle. At the same time, the system keeps a spring brake held off by that air pressure; the spring brake acts as a fail-safe parking/emergency brake. If air pressure is lost, the spring brake automatically applies, bringing the vehicle to a stop. So this type of system relies on air pressure both to release the parking brake and to actuate the service brakes for stopping. The other options describe hydraulic, mechanical, or electric braking approaches, which are not air-actuated.