How can the existence of leaks or lack of airtightness in the pneumatic braking circuit be checked?

Question

DentroTest · Accepted Answer

The airtightness of a pneumatic brake system is essential so that pressurized air is available when the service brake or the parking brake is applied. It is detected by watching the gauges on the instrument cluster: if the circuit is not airtight, there are air losses and the needle drops below the working pressure instead of staying steady. A pressure exceeding the maximum because of outside air entering is not a sign of a leak: a leak causes loss of pressure, never overpressure (the maximum is controlled by the pressure regulator or unloader valve). And checking the air level in the tanks by eye is useless, because compressed air has no physical level that can be seen.

How can the existence of leaks or lack of airtightness in the pneumatic braking circuit be checked?

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