Why must air tanks be drained?

Air tanks must be drained primarily to eliminate any water or oil that accumulates within them. Compressed air contains moisture which can condense and collect in the air tanks, especially in humid conditions. If this moisture is not removed, it can lead to several mechanical issues. Water in the air supply can cause problems in various components of the braking system and other pneumatic systems, leading to corrosion and freezing in cold weather.

The presence of oil can also interfere with the proper functioning of air-operated systems. Keeping the air tanks clean and free of moisture and contaminants is essential for maintaining the efficiency and longevity of the vehicle's air systems. Regularly draining the tanks helps ensure that the air supplied to the brakes and other systems remains dry and clean, which is vital for safety and performance.