For those following this saga, I am now working on the valve. I have replaced all the bad o rings, but I have no idea what I replace on the regulator valve pin assembly.

Where that white part is, on my gun there are three different discs, seemingly of different materials. They are all gummy and ruined.

Is there a part I can pick up so I don't have to buy the whole thing? Seems kind of wasteful if I can't throw something on there.