The bathtub faucet is leaking at the diverter so the water can't be directed to the shower head. I bought a universal replacement (different brand) and attempted to remove the old one (it was a Delta MAINTSP831CH). After finally removing the small hex screw at the underside of the brass collar, I can't get the collar off the pipe. I applied some lubricant and tried pulling it off, but it wouldn't come off. I then pushed the collar further in to see if there's anything blocking it, only to discover a notch on the pipe which is probably preventing the collar from coming off.
I've replace a few faucets/spout before and even after reviewing the instructions for Delta faucet and the universal one, none mentioned the case with this notched pipe; All the pipes I've encountered are straight and smooth. Has anyone seen this before? Could anyone offer insight into why this pipe is notched and how to get the brass collar off?