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.
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