Repacing blackwater dump valve
I want to replace my Thetford blackwater dump valve because it is frozen in the closed position and I cannot unscrew the screws that hold its two pieces together. I tried the Screw-Out product from Sears but the rusted screws gave out. Drilling out the screws presents a bigger problem because of the heat produced and the subsequent melting of the valves plastic body around the screw holes.
As a side note, if you have a tail light assembly with rusted screws, use a drill to drill into the head of the screw and all of a sudden as the screw head heats up the plastic will begin to melt and the nasty old screw can be pulled out before the plastic cools and hardens once again!
I am thinking of cutting the pipe just above the valve and then replacing the frozen valve with a new valve. Is this a normal procedure?
If I cut the pipe, I think I will be left with a shorter than normal pipe on to which I need to cement the new valve. Would it be feasible to use a rubber sleeve that is made to join pipe sections to join an extension piece to which I cement the new valve?