Why is it important to drain water from the air brake system?

Draining water from the air brake system is crucial primarily to avoid freezing in cold temperatures. When moisture accumulates in the air brake system, especially in cold weather, it can freeze and lead to blockages. These blockages can cause a loss of air pressure and affect the operation of the brakes, which can be dangerous. By regularly draining water from the system, you help ensure that the air supply remains dry and functional, particularly in environments where temperature fluctuations can occur, thus preventing any operational issues linked to frozen moisture.

While the other options do highlight important aspects of air brake system maintenance—such as preventing contamination and enhancing brake performance—these do not directly address the specific risk associated with freezing conditions. Keeping the air system free from water is essential for reliable operation and safety, especially in colder climates.