Practice question

What is the purpose of the one-way check valve in a bus's air brake system?

To warn the driver when air pressure in the tanks drops too low
To let air flow in only one direction so stored air stays in the reservoirs if the compressor or supply line develops a leak
To automatically drain moisture and oil from the air tanks
To limit the maximum road speed of the bus

Answer: B — To let air flow in only one direction so stored air stays in the reservoirs if the compressor or supply line develops a leak

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