Trim fiberglass or something else?

[plumbing rookie]

Hello folks. So I'm trying to fix a leak for the hot water in the shower. The problem I'm running across is the hole in the fiberglass is just barely big enough for the valve stem wrench to go in and the nut at the base of the stem is a little off-center, so I can't get the wrench on the nut. Am I going to need to trim the fiberglass back or do you guys have another suggestion? If I do need to, how would you suggest as the best way. The only thing I can think of to do is to drill some holes in the fiberglass around the hole, then use some plyers to pop the piece out. Thanks for any help you can offer.

 

[Twowaxhack]

I use a dremel tool or a drill. Sounds like you’ll do fine.

 

[breplum]

You call out a 'valve stem wrench'.
A purpose designed deep socket is what we use

 

[FishScreener]

Mark the outside of the trim piece with a dry erase marker. Move in about 3/4-inch from that line and you can trim out that far. When you get done trimming the fiberglass the dry erase comes off easily.

And it might be easier to go in from the other side of the wall, if you have a closet behind it, that might be easier to fix, or put an access door over. You get a lot more room to work that way.