Air Brake Practice Test

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Study for the Air Brake Exam with flashcards and multiple choice questions. Each question includes hints and explanations to boost your knowledge. Prepare now and ace your test!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

Practice this question and more.

What is primarily responsible for holding air inside the tank when the air compressor is spilling?

The tractor protection valve
The emergency relay valve
The one-way check valve
The air dryer

The correct answer is: The one-way check valve

The one-way check valve plays a crucial role in holding air inside the tank when the air compressor is spilling. This valve allows air to flow in one direction—into the tank—and prevents it from flowing back out. When the air compressor is active, it pressurizes the air and sends it into the air tank; however, if there is a need to stop or if the compressor is malfunctioning, the check valve ensures that the compressed air remains contained within the tank. This function is vital for maintaining pressure in the air brake system, as it ensures that there is a readily available supply of air for braking even when the compressor is not actively working. Without a one-way check valve to hold the air, the brake system could suffer from a loss of pressure, leading to ineffective braking and potential hazards on the road.