I'm trying to replace an old shower faucet for my 87 y/o father-in-law.
Bought a new single handle faucet and took the old one off. that's when the
fat lady started singing.
This house was built in the 1940's. There is a round plate with 4 screws. I
removed the screws expecting to see a hot and cold pipe. No such luck.
Inside was 2 brass cylinders (1 hot, 1 cold) The stem had large threads that
mesh with the 2 cylinders for water temp control. No way can I remove the
inside piece to connect to the new unit, plus it would never fit. I guess I
need to find an exact replacement. Any ideas of where to look?

thanks
Phil in miami