[BusNit]

I could cap off with a push on plug the 1/4” drain and open both valves but I’m thinking if this happens on the road a service port to the tanks might make quick work.

Both tanks have been cleaned and powder coated. Interior has been sloshed with rust inhibitor coating. (Red material that they use on steel building purlins)

All this did work fine but I let the coach sit un-aired for weeks after I tested it all. There are new check valves on both front air tanks as well as protection valve. (All Bendix brand) all inlets are top side. Drains at bottom and new service port will go on unused 3/8” side tank port.