I have a similar problem, any plumber help is much appreciated.
my shower/tub handle broke while turning it. when I unscrewed everything, I see the cartridge white plastic eaten up and the post I believe its called ( the round metal brass bolt in the center ) of the stem broken in the handle.
so a removal tool was useless, i got a free replacement cartridge Moen 1222 from HomeDepot, no way to tell my model, except i checked all shower/tub handles on Moen website and it seems they all use 1222. the 1222 still doesnt look like my cartridge, mine has very white plastic, the house was built around 2000.
anyway i drilled 2 1/8" hole in the plastic and put in the holes self drilling screws, tried to twist the screws with a nut wrench and the screws bent and the cartridge didn't move at all, and the plastic broke, i can now see the metal and one round rubber came out.
I tried using a 1/4" self drilling screw in one of the holes but it was too close to the pipe so I stopped.
I have used vinegar. nothing.
now that the plastic broke a bit I can see the post (the round metal brass bolt in the center) which is about 1cm long, I tried to pull it with pliers, and couldn't cause I cant reach deep enough to have a good grasp.
I called a plumber Mr. Rooter he wanted around $1000 to fix that along with 2 dripping faucets.
I cant afford that. he told me they overcharge because I called the company directly, he said I could find a self employed plumber to do it for $300, but I don't wana call someone from google.
I'm gona buy the Lasco 13-2125 removal tool if i ever get the stem out.
now I'm thinking to drill the the round metal brass bolt in the center and use a tap and 1/4" bolt.
I'm just afraid that the metal dust and shreds will contaminate the water.
I had also water leak from the cartridge to the inside wall and into the living room downstairs the first day, until I realized after 24 hours and fixed it with tape.
it was bad, and I am now afraid of mold or termites. especially that water leaked before when I was cleaning the toilet few months back, I don't know how water leaked to living room, apparently from the floor to behind the baseboard. they make these houses in cardboard boxes ?!
do I have to tear down the dry wall to check for mold ? I have a newborn in the house and read that it can be dangerous.
around the pipe is black tape to avoid leaking inside wall.
thank you.