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Air pressure problem

The coach has been sitting in the driveway since January.  Lately, I have been doing some maintenance: LOF, interior punch list, new entry mat, etc.  About 2 week ago, I put on a new reman air dryer.  I have done this twice before so don't think I made any errors.  I marked which way the air line connectors should point and think I got them hooked up to the correct lines.  I started it up and built pressure to about 100psi and checked for leaks.  All seemed good.  I did not run it until the compressor unloaded.  I know now I probably should have.

Tomorrow I have an appointment to have a front hub inner seal replaced so I went out today to make sure I was ready to roll: travel mode, air pressure, VMSpc, etc.  Coach would not build air pressure.  I went around to the back and could hear a pressure relief sound about every sec.  Psssst, Psssst, Psssst, .....  Not too loud but noticeable.  Sounds like it is coming from the right rear, above and to the right of the air dryer.  Kind of below and just left of the coolant tank.  I can it it fairly distinctly if I put my ear on the tube from the intercooler to the turbo.  I bubble checked the air dyer and D2 but found no leaks.  Not coming from the retarder valve.  I can't think of anything else that would be in that area.

As far as I know, the D2 is original so I replaced that.  No change.

So I by-passed the air dryer.  It will now build pressure and the compressor will unload at about 120 on the dash gauge.  There is a fairly loud clanky sound from the area of the wet tank while the compressor is pumping. 

Any suggestions?  Any reason I can't drive about 4 miles to the shop in the morning?

Thanks in advance for the help.

Rich
Rich and Peggy Bowman
2002 U270 3610 WTFS, build #5939--"Freedom"
2022 Jeep Grand Cherokee Summit 4xe
SMI AirForceOne brake system
PakCanoe 15

Re: Air pressure problem

Reply #1 –
Rich,
Is there any air coming from the drier at an intermediate pressure with the engine off?
Regards,
Brett

'99 42' Foretravel Xtreme
'14 Brown Motorsports Stacker
'05 Chevy SSR
'02 BMW R1150R

Re: Air pressure problem

Reply #2 –
Quote from: Rich Bowman –

So I by-passed the air dryer.  It will now build pressure and the compressor will unload at about 120 on the dash gauge.  There is a fairly loud clanky sound from the area of the wet tank while the compressor is pumping. 

Any suggestions?  Any reason I can't drive about 4 miles to the shop in the morning?

Thanks in advance for the help.

Rich

I don't see any reason.  Air and vacuum systems in quiet locations have mufflers installed in the plumbing.  Just sayin'.

It doesn't hurt to drain the pressure tanks after a long trip.
1992 Foretravel Grand Villa
U225 SBID Build No. 4134
1986 Rockwood Driftwood
1968 S.I.A.T.A. Spring
1962 Studebaker Lark
1986 Honda VF700C
1983 Honda VF750C
Charlie, the Dog was broken out of jail 24 Oct 2023
N1RPN
AA1OH (H)e who must be obeyed.

Re: Air pressure problem

Reply #3 –
Took it over this morning to have a wheel seal replaced.  Reconnected the dryer and now it works fine. 

The system was air tight and not leaking but would not build air. 

I'll continue to monitor.  It was a good excuse for a new D2 governor and I also now know my dryer bypass kit works.

Rich
Rich and Peggy Bowman
2002 U270 3610 WTFS, build #5939--"Freedom"
2022 Jeep Grand Cherokee Summit 4xe
SMI AirForceOne brake system
PakCanoe 15