Disassembled the unions on my Hayward H400 to replace the o-rings since one was leaking. Outlet union nut went on fine. Inlet won't thread on. It keeps jumping off on one side or the other, resulting in a crossthreaded connection. Anyone ever had either the header or the nut go out of round? What obvious thing am I doing wrong here?
I'm about at my wits end on this one since the original installers glued everything together in ultra-tight bends so the filter is only a few inches away from where I'm trying to work. If that nut is bad, then I have to replace my filter inlet male nipple, the whole assembly of elbows and pipe, and the union as well. All the elbows are close-fit so there's no spare pipe in between where I could cut, slip on a new nut, and re-join with a coupler.