I'm trying to replace my 20 plus year old delta shower single level faucet. I've removed the lever handle, and unscrewed the backplate. I'm uncertain how to remove the the center portion that will give me acess to rough plumbling. Unless it is on bottom, I see no evidence of a hex screw to remove. I've tried to slide it off and used my large plyiers to try and unscrew it. I did not want to break it, so I left it alone. Is this enough information for anyone to provide any suggestions on my next step.
The dome cap under the handle is unscrewed by turning it counter-clockwise. Grip the threaded base of the cap with a pair of channel-lock pliers or a small pipe wrench. Once you break it loose, it should be easy to unscrew. Usually the threads just get corroded and need a little persuasion.
With the dome cap off, the ball and rubber seats-and-springs will come out. I use a small screwdriver or icepick to get the seats-and-springs out.
I recommend replacing all parts with a genuine Delta repair parts kit.