Midland Compressor never shuts off?

[dansautosales]

I recently purchased a 1971 M352A, Deuce and a half cargo truck. When I purchased it the air line from the block under the dash to the air pressure gauge was missing. I plugged the hole and that stopped the air leak. Now I noticed that when the truck runs the Midland air compressor runs continuously and never shuts off. The pressure keeps releasing under the truck midway back. My question is shouldn't the air compressor cycle in and out? And if so does it have a cycling switch? What would make the compressor run non stop? Thanks for your help.

 

[frodobaggins]

The compressor never shuts off. There should be an air governor that blows on and off.

 

[DieselBob]

You might want to checkout this tread

http://www.steelsoldiers.com/deuce/36059-air-governor-questions.html

The air release under the truck is most likely the safety valve blowing off.

 

[dansautosales]

So if the air governor isn't working as it should would that cause air to keep blowing out of the pop off valve?

 

[rat4spd]

If the compressor is not unloading via the governor, and always pumping air, something has to give, and that would be the safey valve (pop off.)