For leaks I would check the air leveling valves first, then the push on connectors, both these can have minor leaks. When mine was leaking more than it is now I could just hit the air dump and level the coach. Mine was the rear leveling valve on the drivers side. It still worked and I could not see it leaking by spraying it with soapy water, but once I replaced it it held air and the needle remained steady for days. I kept the old one for an emergency spare.