High air pressure won't adjust.

[ldmack3]

My buzzer would shut of at exactly 60 psi and when I confirmed the overpressure the additional gage it read the same. Now seems all is well.

 

[ldmack3]

Reviving this old thread as I'm having the same trouble again.

After not being run for 3-4 months I plumbed air into the connection by the passenger to check the gage and the horn that had been removed for fender work. Gage was accurate but horn emitted a squeaky sound that continued after power off until I release the air pressure.

Pulled the solenoid and under the elbow connection was some dirt caught in the screen. Cleaned it out, checked the solenoid and it was letting air through all the time, although a small amount. Blew air back and forth while jumping the electrical connection on/off and it finally completely shut off the air. Reinstalled and still had a squeaky horn but only when I hit the switch.

Pulled the horn and disassembled, amazed how simple it is. Had a lot of dust in it. Cleaned, reassembled, reinstalled and now worked correctly.. OMG I love that sound!

Finished up what need be and ran the engine after 3-4 months. High air pressure again. Fixed it last time by replacing the governor, or so I thought. Problem is never ran it after the one time it tested good.

Adjusted the governor all the way CCW to no avail.

Since I found dirt in the horn I'm working on pulling the air lines and blowing out with compressed air. So far nothing but some black oily substance from the compressor. Next is to pull the new gov and look for contaminates.

Should all this check out I'm betting on the unloader is bad. Is this a replaceable subassembly or will the entire compressor need to be changed? (ouch!)

Any other ideas?

Thanks all.

Forgot to mention. While the horn was out I connected the shop air again and something, like dirt or rock blew out the open line to the horn. It bounced off so could not determine what it was.

 

[HDN]

I put a gauge in my line of sight, teed off my tire filling manifold under right side of dash.
I eyed that gauge always as no air=difficult stop. I could see the air regulator functioning.
I had suggest installing this manifold to all to air up tires safely, hook it up and stay on other side of the truck.
It proved the in-dash air gauge and buzzer to be inaccurate.

I use an in-line air gauge on my tire hose connected to the emergency gladhand and used that to verify that the compressor is cutting in and out at the proper pressures. It seems to be consistent with what the air gauge on the dash reads, thankfully!

 

[ldmack3]

After blowing out the lines and checking the gov it was still high. So just for grins and giggles I thought maybe the manual was wrong on the adjustment...

It's WRONG!
CCW is to increase the pressure not decrease. Adjusted it for should be more pressure and it came down. Got it close running stationary but will readjust after driving it. Probably did not need the new gov.

Effen manuals!

 

[M37M35]

Finished up what need be and ran the engine after 3-4 months. High air pressure again. Fixed it last time by replacing the governor, or so I thought. Problem is never ran it after the one time it tested good.

Should all this check out I'm betting on the unloader is bad.

My money is on there being an issue with the new governor. I'd take it off, clean it, and spray some WD40 in it before I messed with the compressor. Maybe even put another new governor on it.

 

[HDN]

After blowing out the lines and checking the gov it was still high. So just for grins and giggles I thought maybe the manual was wrong on the adjustment...

It's WRONG!
CCW is to increase the pressure not decrease. Adjusted it for should be more pressure and it came down. Got it close running stationary but will readjust after driving it. Probably did not need the new gov.

Effen manuals!

Well, guess it's time to submit errata



I'm glad you got it all worked out! Makes me wonder how many of those components were replaced in-service with this error!

 

[M37M35]

After blowing out the lines and checking the gov it was still high. So just for grins and giggles I thought maybe the manual was wrong on the adjustment...

It's WRONG!
CCW is to increase the pressure not decrease. Adjusted it for should be more pressure and it came down. Got it close running stationary but will readjust after driving it. Probably did not need the new gov.

Effen manuals!

Well there you go!

 

[frank8003]

The girls like to run, they don't like being left laying around at all..............................
She ain't no Toyota, She a tactical 50 year old military truck [at least] to do WAR business and pull big heavy stuff.
Needs to be used, maybe, within reason, can not be used up.