For what reason might the air tanks (reservoirs) of a truck fail to reach the required working pressure while the engine is running?

Question

DentroTest · Accepted Answer

In heavy vehicles with pneumatic braking, the engine-driven compressor generates the compressed air that is stored in the reservoirs or tanks. Under normal conditions, right after starting the engine, the pressure rises quickly until it reaches the working pressure. If that pressure is not reached with the engine running, or it takes an abnormally long time, the fault is usually due to a leak in the lines, valves or connections of the pneumatic circuit (or, failing that, to a fault in the compressor or the pressure regulator). Wear of the pads or shoes, on the other hand, is a purely mechanical matter of the friction elements and does not affect the system's ability to generate and retain air pressure.

For what reason might the air tanks (reservoirs) of a truck fail to reach the required working pressure while the engine is running?

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