[TJ Clark]

Break Air builds. Can hear the compressor cut off compression release at approximately 130 pis. But no supply side air at the gage. I am not hearing any air leaks.


Had the 120v  compressor running with the engine and it never stopped even when the compressor compression release opened. None of the supply side system are operating. Between the 120v not cutting off and the air seat not rising I am guessing it is not just a dash gage issue. 

Where do I start trouble shooting?

[Richard]

Pressure protection valve on bulkhead in front of drive axle.

Check valve on the tee fitting going into the ping tank in the passenger drive wheel well.

[TJ Clark]

I just tried it again and it aired up.

The only change is the temperature. Was low 40's nor high 50's

---

Pressure protection valve on bulkhead in front of drive axle.   

What side? 


Check valve on the tee fitting going into the ping tank in the passenger drive wheel well.


Tom and I are about the same size Is this tank between the frame rails? 

[Richard]

PPV is in the middle. Google will give a picture of one.

The tank is in the front of the wheel well.

[Richard]

TJ

Do you have a 12V aux compressor? If so, the next time you lose the supply air would you try the 12V compressor and see if you get air to the potties doors and slide seals. If so that narrows the problem to the PPV since the 12V plumbing does not go through the PPV.

[TJ Clark]

12V compressor operating and those systems functioning normally.

I did a several hour test yesterday checking the cycle intervals and run times for the 120v compressor. Started off at 40 minutes between cycles, with a 7 minute run time. As the temperature dropped the cycle interval decreased and the run time increased.

Might mean nothing.

Once the times neared equal I turned off the 120v compressor. The supply side dropped to 0.0 psi rapidly and the break side registered 45-50 psi.

[Richard]

https://www.youtube.com/watch?v=7rnRcyW96m4 If will take the time to watch, it will help explain the plumbing.

You obviously have a big air leak somewhere. It is common for leaks to get bigger as the temp drops. Many times that has to do with the tubing shrinking in the push on connections.

[cwl1979]

Does the engine compressor build air like it should, but wont switch over to the supply air? Change the pressure protection valve, they are cheap. https://www.amazon.com/Meritor-S93489940...1_8?sr=8-8
Once that is changed if problem persists there are other issues that it could be.

[TJ Clark]

Richard:
Just finished the video series. Thanks for reminding me. In the last of the series you t6alked about fittings and posting an invoice from McMaster Carr. Do you have a link to that post?

Back to the current issue. I think I clearly have an air leak or several. I don't think I am going to find them parked in the woods. I'll need to find a pit or a skinny guy to help with that. Tom and I are about the same shape.


Carl:
Yes once the t4emps warmed up later that day it aired up normally leveled out to ride height normally, and the compressor shut off normally.



Thanks

[Richard]

TJ

I can’t find that document, too many sleeps since then.