Old shower faucet
Thank you for the response. I thought that may have been the case. So here is my next novice question: if I do remove the existing arm and attach a new arm ( using thread sealant tape or goo) how do I know that the arm is fully seated in the fitting and is not leaking without being able to see the fitting clearly behind the wall? That is to say, if the arm is leaking at the fitting and dripping behind the cement board, I probably wouldn't know until I started seeing significant water damage, right?