I've got a simple two-valve shower (no tub). Hot & cold handles each protrude from shower wall about 3" with simple twist operation handle mechanisms. I need to fix a leak in the cold handle (it runs when shower is on; no leak when off). I figure the cartridge assembly needs repair, and there's plenty of DIY information available on how to do this... but it all shows a very simple process of removing the handle, pulling out the stem and disassembling. I can get as far as taking the handle off, but a) the stem doesn't just pull out, and b) the cartridge is recessed very snugly inside the 3" of pipe connecting it to the plumbing behind the wall - so visibility is limited back there!
I'm afraid to go any farther, i.e. force the stem. Is it supposed to just pull out? If not, how can the repair be done given that the parts are housed inside pipe? (p.s. I don't mind calling a plumber ! Just rather not use a vacation day if this truly is a simple DIY job.)
Unscrew it counter-clockwise with a strap wrench or use a cloth over it and unscrew it with a pipe wrench or pair of channel-lock pliers.
You also may need a set of plumber's valve sockets to remove the valve and replace the o-ring that's leaking (and replace the washer while you have the valve out).
Turn the water off first, of course.