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Topic: trouble shooting air leak (Read 398 times) previous topic - next topic

trouble shooting air leak

I took "Moe" for a exercise ran, and the FT preformed flawlessly.  Air pressure both gauges 115psi and drop to 90 psi. System was 0 psi when starting it, however, it rapidly climbed to 115psi. I used retarder and it worked great. When I got back home and parked, I noticed the air gauges where going down, And by the next morning they were at 10psi. It has never done that, usually it holds air pressure never going below 40 psi for over a month.
Where do you recommend that I start my search based on the above information?  Thank you for any help.
John
1998 U270 34'

Re: trouble shooting air leak

Reply #1 –
Start with getting it up to pressure and shutting off engine and crawl under and listen for leaks and go from there,block coach with
the blocks and start tighening every air hose connection,see what that does and re-evaluate.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: trouble shooting air leak

Reply #2 –
John, make sure the drain valves are closed on the service tanks are closed, not likely the problem but check.  Both of my tanks are leaking down now faster than I want and both of my pressure protection valves are leaking.  One on each tank connected to the tans and from that air lines.  Use some soapy water to check.  If it is a big leak you will hear it.  Mine sound like someone is under the coach snoring.  To change these out you have to disconnect lots of fittings.  Every connection is a possible source for leaks.  Use care reassembling them.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: trouble shooting air leak

Reply #3 –
Quote from: John/Pat –
When I got back home and parked, I noticed the air gauges where going down, and by the next morning they were at 10psi.
SO, your air compressor works and D2 governor works...two items you don't have to worry about.  :thumbsup:

Based on your reported symptoms, besides your "new" air leak, I would say you have one of the two situations described below.

A.  It could be that both of your pressure protection valves are leaking.  If your "new" air leak is downstream of the protection valves, and they were working, then your front and rear brake tanks would drop to about 60 psi, and then the pressure would hold at the point.

OR

B.  It could be that your "new" air leak is upstream of the front and rear brake tanks, and the inlet check valves on those tanks are both leaking.  If that were the case, your wet tank, front tank and rear tank would all suffer the same simultaneous pressure decline due to the "new" leak.

These are the only two scenarios I can think of (at the moment) that would explain both air gauges dropping simultaneously to 10 psi.

Once you have discovered (and corrected) the location of your "new" air leak, then you will also need to address either A or B above.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"