The Thetford waste drain valve from 1969 leaks when closed. What a surprise after 40+ years.
I removed the valve, and bought a seal replacement kit. Here's the kit I bought, which I THINK is the right kit, but I haven't opened it yet, in case it needs to be returned.
Here's the critical piece of the valve that needs to be disassembled so I can get to the seal inside, which is failing to fully seal.
The problem is that at the four points where screws attach this valve to the rest of the valve body, there is a brass sleeve through the valve body, which is flared at both sides so that even with the screws removed, it holds the valve body together. Maybe these pics will show it better:
So how do I remove the stainless steel backing plate from the plastic valve body so that I can get to the seal inside? Any ideas?