Arizona Air Brakes CDL Practice Test

Why is it important to drain water from the compressed air tanks?

1. To keep from fouling the air compressor oil.

2. Water can freeze in cold weather and cause brake failure.

3. The low boiling point of water reduces braking power.

4. Water over cools the compressor.

The correct answer is: Water can freeze in cold weather and cause brake failure.

Draining water from compressed air tanks is crucial primarily because water can freeze in cold weather, leading to brake failure. The air brake system relies on compressed air to operate effectively, and the presence of moisture can cause ice to form in the air lines or components, such as the brake valves or cylinders. When this happens, the air can't flow properly, potentially inhibiting the braking system's ability to function. In addition, while other factors like air compressor oil fouling and cooling concerns play roles in vehicle maintenance, the formation of ice due to accumulated moisture poses immediate risks to safety and brake effectiveness. As such, regular draining of the air tanks is a vital preventative measure to ensure reliable braking performance, particularly in harsher weather conditions.