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Mystery Air Leak
Have owned my coach for over 5 years now and quite accustomed to dealing with air leaks, but this one’s got the best of me
Loosing 50-60 Lbs in 15-20 minutes on aux air tank (which should be enough to hear). ONLY happens with power switch & ignition in the on position. Power switch & ignition off I only loose about 10 Lbs in 12-16 hours (more than acceptable).
Have new air bags, all new Norgren valves, and about 90 percent of my fittings change out to compression fittings.
I bring the system up to 125 Psi, block the tires, leave the parking brake off and the key on (engine not running). Walk around the coach carefully listening and hear nothing.
While driving on the highway I can watch the Aux tank drop down to about 95 Psi then back up to 125 about every 10-15 minutes. Brake tanks remain at 125 while traveling down the highway.
What am I missing that I can’t find a leak of this volume?Chuck
P.S. When parked Coach stays level for weeks, so it appears air bags and Norgren are working properly
2000 Featherlite H3-45
2024 Jeep Grand Cherokee
Leesburg, FL -
21 Replies
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maybe a loose armature/bad o-ring on the 5 stack?
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Don:
Did fix a air leak in there a couple of weeks ago. Changed a push on to a compression. That was a lot slower leak and I could clearly hear it. Not hearing anything or seeing (with soap) anything in the 5 stack area.
Really got me stumped. Had may leaks slower than this one and could easily hear them. leaking 20-30 PSI in 10-15 min is a pretty good leak that I should be able to hear. Know I am getting older, but geezzzz.
Chuck
P.S. Not sure but I think I am hearing a leak up between the tags?
2000 Featherlite H3-45
2024 Jeep Grand Cherokee
Leesburg, FL -
This may be a long shot, but might be worth looking at. If the PPV, on the aux tank, has failed and is allowing air to flow back towards the compressor when the compressor has cycled off, it can show this condition. You don’t see it in the main tanks as those check valves have not failed. This could explain why you cannot hear it.
2000 Featherlite H3-45
2024 Jeep Grand Cherokee
Leesburg, FL -
Mike:
We think the same. First thing I did was to rapidly pump the brakes down, the aux went to 90 Psi and stopped. Next I dumped the Aux and the brake tanks stayed up.
We are traveling and at a quiet campground this morning. Aired up, blocked the wheels, turning Eng off, left key on, can see gauge slowly dropping but still can’t hear a leak. Think I hear something between the tags but can’t confirm. At the rate I am losing air I should hear it
Chuck
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I think it has to be in the level low system, in the travel mode maybe a level valve?? most everything on aux system is always activated,step well-door lock-air horn if you have door slides, do you have slides in bus? They may only work with key on?
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Art
I have isolation valves on the drivers seat, step well cover, generator air bags, air horns, rear view pop out camera, and engine belt air bags. Have shut off all isolation valves and still have leak.
I am a Florida boy and my bus is a Florida bus, BUT we are currently on a trip to Branson MO for their Christmas season opening. Supposed to be getting in the 20s, so maybe the cold will make the leak easier to find.
Chuck
2000 Featherlite H3-45
2024 Jeep Grand Cherokee
Leesburg, FL -
That’s what I’m saying,you said it’s only happening when the key is on so the level low is affected by the key not all the other things
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Don
Think your the winning diagnosis. Got to 28 deg last night, started bus this morning and center of 5 stack is leaking. Wiggle it and it stops, wiggle it again and it starts leaking. Don’t know if this is the big leak, but it’s definitely a leak.
Do I need to replace just the electric portion, or the little shaft that the electric solenoid slides on?
Chuck
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Change the armature and/or tighten the armature (valve) down with the 2 screws holding it to the manifold base. That may fix it. There are 2 O-rings under it.The valve is called (by Norgren) an “armature”, Norgren pt # 54462-31, available from a norgren.com dealer and/or ebay.The electric thing is a coil, either 12vdc or 24vdc.12v = Norgren pt# 54452-02, or 24vdc = 54452-03.
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Changed the Middle valve (armature), air loss over all slowed substantially but there are still more leaks to find…
Screws were rusted in and almost broke off when removing. Scared to attempt the others while in middle of a trip. Plan on ordering complete new 5 stack (minus electric solenoids) and replace when at home.
Got all my leaks to a minimum before leaving home knowing the cold would create more. Wow wasn’t ready for this level of more leaks. O well, at least I am finding leaks. Some days I think getting all the air leaks stopped would be like winning the Lotto (extremely low probability but great pay off)
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When we 1st bought the bus 8 years ago it would lean to passenger side after about an hour or so, I replaced all air bags, they were in bad shape. Once I started to learn about the system the aux gauge would drop to 0 in a hour or so and primary and secondary tanks after 24 hours would do the same. Driving down the road next to a K rail I hear the dryer cycle every 5 to 10 minutes and started watching aux gauge and it would cycle from 120 to 100 at the same time. I replaced the governor on dryer and I replaced the unloadervalve kit and replaced air dryer with a Bendix AD9 dryer. After that driving aux gauge does not move driving down the road unless I hit the brakes. Sense then I’ve replaced all Norgrenvalves 1 level valve valve on 1 side of rear, system is pretty tight, In winter cold it still does lose a little air while parked at home, I’ve decided that’s good enough.
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Art:
Your reply “I have decided that’s good enough” reminds me of my father in laws saying – “Good enough for the guy that lives here” LOL
Chuck
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We owned an ’88 that we bought in ’99. Chased leaks for about 19 years before the coach was “prefect”. Sold it at 20 years and now are working again to get this ’98 to hold air. We travel full time so can really work on much of this ourselves so we go shop to shop trying to get help. Prevost is the least helpful (or successful) as they really don’t seem to want to be bothered.
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Ordered new 5 stack ride Height manifold and installed.(manifold ,valves,& solenoid package was only $385) Still loosing 25-30 Psi every 5 minutes while driving. With key off rapid leak slows to 20 Psi loss in about 8-12 hours.
This leak is driving me crazy, at the high rate of air loss with the key on I should be able to find it.
As noted earlier, all air bags and norgren valves have been replaced and about 90% of the push on fittings have be changed out to compression fittings over the last few years.
Running out of ideas.
chuck2000 Featherlite H3-45
2024 Jeep Grand Cherokee
Leesburg, FL -
Hello Chuck – since a significant leak appears when the key is on, seems that would limit your search to electrically energized air components.
Have you checked all solenoid valves that allow air to pass thru? What about the points where electrically operated norgens supply and exhaust. Agree with you that after turning on the key, and then checking / listening for the leak should be productive. Sorry you are having this issue. Perhaps it is the “device” that receives air once a solenoid or norgren is opened after the ignition is turned to the on position.
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