As has been way to much the case lately, I have been chasing air leaks from our onboard compressor setup. It seems every time I get it to hold, it reverts after some driving and use time. The leaks I have found in the past have all been in the feed tubing connections or in the fill control panel. There has not ever been a leak on bag side, beyond the controller. The compressor always seemed to run in the middle of night, just to wake us up.
We have a Firestone onboard compressor that powers our airbags, through a dual controller, feeds a tire fill hose port, and also inputs into the air powered spare tire lifter. That makes the air feed split to 4 inputs, with two outputs to the bags. That is a lot of inline tees and fittings, all unsupported and inline. The controller (two needle gauge and two valves) had the output and gauge inputs connected using unclamped small barb fittings, which are a terrible choice for hard nylon tubing, and prone to leaking if flexed much at all, or if the barb is nicked when you replace the tubing.
I decided to get rid of the barb fittings, even though it meant more full size fittings, and two extra tubes to the controller. That gave all OD sealing on the tubing, like it should be. I wanted to get rid of all the push connectors, also, but the control valves, bag connections, and tire fill port are all push type and not easy to get other connections for. For everything else I switched to standard airbrake nut/sleeve/inner supt brass compression fittings, which I have found to be much more durable and leak free than push fittings (the push fittings seem to be OK if the tubing can't move around at all, though). To get rid of all the heavy fittings hanging on the tubing, I built 3 manifolds, one for the inlet air, and one each for the outlet to each bag, which now had to also feed back to the gauge inputs. The manifolds are bolted to the side storage pod where the controller is mounted, so the tubing is not supporting anything but itself.
Here is what it looks like from below
Closer of the manifolds, which are made by silver soldering together regular brass pipe fittings. It is really a neat way to make manifolds, as they are more compact without the nipples in between the fittings, you can aim them any way you want, they never come loose, no machining,and are easy to attach brackets to. They are also very quick and easy to make. These took less than 10 minutes each. Machined ones would take hours.
The tubing goes into the side storage though oversized holes, so they got gooped up with silicone to seal them up.
Everything turned out very nicely, except it still leaked a little bit, and would run about every 48 hours, so I replaced the push fittings on the compressor and tank with compression fittings. It still leaked the same, so I took out the check valve from the compressor to check it. It seemed to be sealing inconsistently, so I cleaned it and put a bit of air tool oil in it. That took care of the leak, and it will now go well past two weeks without running. I did order a new check valve in case it starts to leak again, and when it arrived, it was a different style, so they must have had trouble with the originals.
We will see if leaks come back after driving, as they have in the past.