[77newell]

You are getting a lot of good suggestions, but are missing a troubleshooting strategy. If you seach this site you will likely find a schematic, or a close facsimile, that will help you find valves that will allow you to break the system into segments which vastly speeds up locating the leak(s). You are otherwise searching through a seemingly endless barrel of snakes with increasing frustration.

There are a couple valves near your supply tank that allow isolating the two segments of the non-brake air systems. I would start by shutting both off and watch my air pressure gauges to identify the segment that is leaking and work from there.