pgp non-cartridge valve chamber plug sleeve question
 

I have a leaky non-cartridge valve PGP. it was an abandoned semi-project.
It leaks several places, I've ordered a valve seal kit for it. I think this may fix a majority of leaks.

The thing that bothers me: I took it apart and it seems to be missing the chamber plug sleeve. Instead it had an o-ring similar to the one on the exhaust valve.
Can you replace the chamber plug sleeve with an O-ring ?
I imagine that if you could it would need to smaller than the one that was in there. (to fit inbetween the bigger sleeve/shelve and the chamber plug face. To fit in the same fashion as the original sleeve.)
Any advice is appreciated.

there is no o-ring that goes between the brass sleeve and chamber plug. the o-ring goes on the chamber plug itself and is smaller than the o-ring that goes between the exhaust valve and brass sleeve.