I unscrewed the knob and pulled it off, then took of the escutcheon, then removed the entire valve body. The stem screws in and out of the valve body which is what controls the water flow. The valve body is smooth and has a rubber o-ring at the end of it. My question is what holds the valve body in the seat? The body just keeps spinning when I turn the handle. I read this on another forum which sounds similar to my problem:
"the hold down retaining nut that you remove that secures the stem in the body needs to be very tight so the barrel seat will not move. some of the barrels have an "O" Ring seal at the base and can cause the barrel to slip, so tighten it down real good. Let me know if that helps...."
I did make the nut pretty tight, but it still spins. Any other ideas?