What does an air dryer do in a modern air brake system?

Pick an answer

1. It increases the temperature of the compressed air slightly as a side effect of drying it, which is incidental and not its primary purpose
2. It removes moisture from the compressed air before it reaches the tanks, reducing the contamination that draining alone has to handle
3. It dries the windshield using leftover system air
4. It replaces the need for a governor

Correct!

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