Arizona Air Brakes CDL Practice Test

An air tank drain valve is used to remove what substances?

1. Air and dirt

2. Oil and air

3. Water and oil

4. Oil and dirt

The correct answer is: Water and oil

The air tank drain valve is specifically designed to remove water and oil that accumulate in the air tanks of a vehicle's air brake system. Over time, condensation can form inside the tanks, especially in humid conditions or after the vehicle has been parked. This condensation turns into water, which can lead to corrosion or damage to the braking system if not regularly removed. Additionally, oil can find its way into the air tanks from the air compressor. If not drained, both of these substances can negatively impact the efficiency of the air brake system and overall vehicle performance. The correct choice highlights the importance of regular maintenance to ensure that the air tanks remain clear of these potentially harmful substances, thus promoting safety and reliability in air brake operation. Regularly draining air tanks is a critical step in preventing brake failures and prolonging the life of the braking components.