Arizona Air Brakes CDL Practice Test

When should air tanks be drained?

1. At the end of each day or shift

2. To keep sludge from clogging brake system valves

3. When automatic devices fail

4. All of the above

The correct answer is: All of the above

Air tanks should be drained regularly to ensure that moisture and contaminants do not accumulate and affect the braking system's performance. Draining the air tanks at the end of each day or shift is a recommended practice to remove any moisture that may have accumulated due to condensation. This helps maintain the integrity and functionality of the braking system. Additionally, moisture in the air tanks can lead to the formation of sludge, which can clog brake system valves and other critical components. By draining the tanks, you minimize the risk of this sludge buildup and ensure that the braking system operates effectively. It's also important to drain the air tanks when automatic draining devices fail. In such cases, manual drainage is needed to prevent moisture from compromising the braking system's reliability. By taking these actions—draining at the end of shifts, preventing sludge buildup, and addressing failures in automatic draining—drivers help maintain safe and efficient operation of the vehicle's air brake system. Therefore, the most comprehensive answer reflects the importance of all these practices, leading to the conclusion that all of the options are correct.