5-ton low air pressure problem, seeking advice.

[babytuck]

I have a 1970, 5 ton military truck with an air pressure problem. Have replaced compressor and governor, will build about 35 lbs. Of pressure but will not hold. Any suggestions??

 

[gimpyrobb]

Put air into it by the gladhands on the front. Listen for air escaping and spray fittings with soapy water to find leaks.

 

[someoldmoose]

Make sure the drain under the left running board is closed.