CDL Air Brakes TestInspecting Air Brake SystemsMedium
A driver is inspecting the air tanks on a commercial vehicle. What is the primary purpose of regularly draining the air tanks?
- ATo ensure the parking brake spring chambers receive adequate air pressure.
- BTo calibrate the air pressure gauges for accurate readings.
- CTo remove contaminants and moisture that can freeze or damage the air brake system components.
- DTo increase the lifespan of the air compressor by reducing backpressure.
Show answer & explanationAnswer & explanation
Correct answer: C. To remove contaminants and moisture that can freeze or damage the air brake system components.
Compressed air contains moisture and oil vapor. As it cools in the air tanks, these condense into water and oil. Regularly draining the tanks removes this accumulation, preventing freezing in cold weather, corrosion, and damage to valves and other components in the air brake system.
Why the other options are wrong
- A. Draining tanks removes contaminants; it doesn't directly ensure air pressure delivery to spring chambers, though a clogged system could impede it.
- B. Draining air tanks has no direct role in calibrating air pressure gauges.
- D. While maintaining a clean system is good, reducing backpressure is not the primary reason for draining tanks.
Air Tank Draining
The process of opening drain valves on air tanks to remove accumulated moisture and oil from the compressed air system.
- Should be done daily, especially in cold weather.
- Prevents freezing, corrosion, and component damage.
- Some tanks have automatic drain valves.
Memory trick: Moisture's the menace, keep it out of your tanks, or your brakes will get thanks... for nothing!