Gary – part #16 (valve retainer) is captured by deformation of the edge of the hole in the housing it sits in. It appears to be the only way to replace part #17 (O-ring).
Do most people just give that one a pass?
Or am I looking at some dremel work?
And why are the core plugs so damned expensive?
ETA: any hints/tips/tricks on removing and installing part #36?