Understood that we’re dealing with Nitrile and Viton, but perhaps worth mentioning here that I was told many years ago not to use Vaseline with rubber seals because it is a petroleum jelly and will eventually encourage the rubber to perish/break down.
They don't clamp it all. The ring just slides down the sides of the opening. That's why folk have so much trouble trying to get a good seal. One bad scratch on the surface and it will never seal. I spent a whole afternoon trying to seal mine, swapping O-rings, changing technique, limiting how far I allowed the flange to go down, etc. It's the one job that has me tearing my thinning hair out.
Yup. Did the same having scratched the sealing surface with a poorly-positioned hose clip. Easy to do.
