Escutcheon screw stuck

[MOB19]

I have a leaky shower valve.

I’ve fixed a few leaky faucets before, so I thought this would be no different, but I cannot even get the escutcheon off to figure out what kind of valve I have.

Both screws on the escutcheon have issues. I was able to back one screw out enough to spray PB Blaster behind the escutcheon and that screw has loosened up enough that I think I can remove it, but the other screw, circled in the attached picture, only rotates an 1/8 of a turn before it completely seizes up. Both screws feel like they are bent.

I’m concerned that if I keep turn the one screw that I will snap it. So my questions are,

1. Any more recommendations on how to loosen the screw up?

2. If the screw doesn’t loosen up, what is a good plan going forward?

 

[Dj2]

What's on the other side of the wall?
A closet?

 

[Sponsor]

 

[Reach4]

You could try carefully cutting a slot with a cutoff wheel on a Dremel tool.

More likely to work IMO would be to drill out the head. Start small, maybe 1/16 inch carefully centered. Then increase the drill size incrementally until you are at the diameter of the screw. Once you get the escutcheon off, grab the screw stub with fine-patterned-jaw locking pliers.

 

[Jadnashua]

FWIW, you may not need to remove the escutcheon at all to replace the cartridge...remove the handle first with the tubular piece behind it and see what access you have.