Arizona Air Brakes CDL Practice Test

What effect does fanning air brakes have?

1. Cools them off

2. Increases the braking power

3. Increases the air pressure

4. Decreases the air pressure

The correct answer is: Decreases the air pressure

Fanning air brakes refers to the technique of rapidly applying and releasing the brakes to manage the vehicle’s speed, particularly in situations where the brakes may otherwise overheat or face other performance issues. When a driver fans the air brakes, they momentarily release the brake pressure, which allows the air pressure in the braking system to decrease. This decrease in air pressure is crucial because it helps prevent the brakes from overheating. Continuous pressure on the brakes can lead to brake fade, where the performance of the brakes diminishes due to excessive heat buildup. By fanning the brakes, the driver manages the temperature and operational effectiveness of the brake system, ensuring safe stopping power without risking damage to the system. Overall, fanning air brakes plays a vital role in maintaining optimal braking efficiency while managing heat and performance in the braking system.