Is the gauge building any air pressure at all? There's a "governor" mounted somewhere on the air compressor that routes air pressure to the valves inside the compressor and holds them open when the preset pressure is reached. Sometimes they stick in the "release" position and prevent pressure from building up. The governor is a round housing about 1 1/2" in diameter and about 4" long, held onto the compressor by two bolts.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!