If air tanks are not drained, what is a potential brake problem?

• A. Brakes may fail due to water freezing
• B. Brakes may fail because of water boiling
• C. The brakes will be unaffected by water in the tanks
• D. Brakes will improve braking when water freezes

Answer: (B)

Moisture in the air tanks can disrupt the brake system because it relies on a clean, dry, steady air supply to operate correctly. When tanks aren’t drained, water collects there, and under braking conditions that water can flash into steam as pressure changes. The resulting vapor pockets can interrupt or reduce the air pressure reaching the brake actuators, leading to diminished braking or a failure to apply properly. This is why a potential brake problem is described as water boiling—the evaporation of water in the system can compromise the brake pressure. In cold weather, moisture can also freeze and cause other braking issues, but the boiling scenario highlights how vapor formation from accumulated water can impact brake function.