-
An Air Leak Question
I need help from the brain trust. My aux pump would go about 24 hours between cycles. I installed the shutoff valves in the converter manifold to my converter installed air devices such as pocket doors, bed lift, seat, generator air bags, drain valves, air horn etc. No change after installing the valves, but recently, as in the last month I am losing aux air. With those closed I am leaking down from 80 to about 40 overnight.
With those open I have virtually the same leakdown rate so I started looking for other leaks. The bus auxiliary air system has the air door lock, the front shutters, the belt tensioners, and of course the suspension.
I have ruled out the air shutter cylinder, the air door lock cylinder, and the aux air tank petcocks. I used the ultrasonic leak detector and soap on them and couldn't hear or see anything. No bubbles, no noise.
That leaves the belt tensioners, belt tensioner valve and regulator, and the solenoid valves in the suspension system. It also leaves the aux air into the norgren valves and I have not yet soaped or listened to those. They are on my list, but I lack confidence anything there is leaking. Those types of leaks tend to show up on the ultrasonic leak detector and I have waved it around all the valves and their respective fittings.
I have checked the compressor and all fittings from the compressor to the converter protection valve. If I have a check valve in that line I cannot see it.
What am I missing? Has anyone found leaks in the aux system that were not where they would be obvious? I know Mango had a leaky regulator on the passenger side near his transmission, but if I have one I cannot see it. and I cannot hear anything with my leak detector or stethoscope.
BTW, with all the valves I installed on the manifold the converter installed I soaped the hell out of it and that is not leaking. Also, If I turn off those valves, and then 24 hours later turn them back on one or two will give a slight hiss when opened to indicate the device they control does have some leakdown, but I cannot see a measurable difference in the air loss with the valves open or closed. Based on the sound of air moving through the valve I suspect they might leak a few bubbles but they are not bleeding off air.
In anticipation of anyone suggesting air bags or other parts of the suspension system there are two reasons I am not looking there. First, the bus will sit without leaning for a long time, and if it went to 40 PSI it would sure be leaning, but second, that air is trapped by the 5 port Norgrens and is isolated from aux system air.
-
How about a leak at the Aux air gauge in the dash?
-
Step slide air cylinder. Check both the shaft end and the air line connection. I think yours is easier to check than mine was. At least I hope it is. When my cylinder went south, it started out as a slow almost impossible to find leak and over time got so bad I had to turn the air off to the slide until I had time to replace it.
-
Check the various air needs of the drivers seat.
Concentrate on the lumbar support.
JIM
-
Jon, At Titusville we found a leak in Pete Petree's Belt Tensioner Valve above the doors. Easy to fix, hard to find.
We are all honored you have asked us for help !
-
Paul, My gauge is on the end of the mainfold. No leak there.
Ted, My step slide is in the converter side of things and I can turn off air to that. No change. Air still leaks even with the valve to it turned off so that is ruled out.
Jim C., Diver's seat, see response to Ted.
Jim K. I have gone over that with the sonic leak detector and stethoscope, but I do have to get out the bubble machine and see if that shows any thing. A one and a two.........
When I start considering how many fittings and components I have to check it makes me want to let it leak. I'm just glad it isn't in the pocket doors, which by the way are the only items on the regulated air supply line and this morning when the air in the aux system was down to 40 PSI, the pocket door air system was still holding at 60 PSI where it was the night before.
-
Check the flange for the diaphragm of the limit switch that controls the aux. compressor.
Check the norgren air filter water drain pet cock.
-
Did the drain valves, but not the diaphragm. If the diaphragm were leaking I suspect my compressor on and off points would change, they haven't, but I will look anyway.
I need Hector's bubbler.
-
Jon, maybe it would be easier to find the leak at higher pressure.
Induce shop air into the system at a higher pressure.
JIM
-
what about isolating the compressor with a ball valve, air up and turn off the valve and see if you loose air?
GregM