Air Compressor: Why won't my air compressor tank hold air?

The check valve prevents tank air from back flowing to the pump. A failed check valve will apply high air pressure to the head of the pump preventing the motor from restarting once the tank has filled. If the motor starts when the tank is empty of air but won't restart when the tank is full, replace the check valve.

Inspect air tube fittings regularly. Firmly tighten any leaking air tube fittings.

The safety valve pops open to relieve excessive air pressure if the pressure switch fails to shut off the air compressor at the cut-out pressure setting. Replace the safety valve if it leaks or pops open at normal operating pressure.

Don't try to fix a leaking air compressor tank. Replace the tank if it leaks air.