I just bought a used DXS air tank. It is leaking around the little pin inside the threaded part that srews onto the marker. Sometimes I can wiggle it around and it will stop. Can I fix this? Is it just an o ring?
Drain the tank and remove the two bonnet set screws, you're going to have to service the regulator or at least clean it.
Careful though, DXS regs are notorious for having globs of green loctite on the bonnet. If you can't get at it take it to your shop.