Air Compressor Cycling Frequently

I'm assuming you have a twin turbo cat? If so you likey have a "system saver air drier. Sounds like the "turbo cut off valve to me. So replace the whole air drier to solve that.

But first try the signal line as mentioned. Then let the truck sit, disconnect the compressor discharge line. If you have any pressure in the line it's likely the check valve on the wet tank.

 

Here is the simplest thing to do first. Let the truck sit for an hour. If your primary and secondary gauges are still right up, open the drain #### on the wet tank. If little or no air is in the tank the check valve is bad and your losing air back into the discharge line. The governor gets the signal from the wet tank.

 

Speaking of Cat fan clutches......... have a friend sitting in nowhere Ohio right now, Cat clutch fan cut loose and took the radiator with it. I'm told they need to go at the first sign of noise / trouble. Ouch!

 

CAT doesn't make a fan clutch. It was probably a Horton or a Bendix. Replace with a Goldtop fan clutch.

 

Holy crap, i had that same issue and i wouldve never guessed that.

 

I had bad leak at fan clutch, but leak detector did not show leak with engine off. that stopped my problem. also. the unloader in the compressor, is a kit u can get for 12 bucks.

 

You can test your fan hub for leaks by turning key on with engine off, the fan hub will release and if there are air leaks they will show.

 

...unloaders eh?

 

Mine had an air leak, the fan didn't come on but the gauge was constantly up and down.

Turning the fan on would stop the leak, it was worst at highway speeds.