Water leaking from shower drains causes damage to subfloors, walls and ceilings. The drain plumbing is difficult to access in some cases, but it is imperative to remove the defective drain. Whether plumbed with PVC or metal pipes, knowledge of plumbing location is the most critical part of the drain removal process.
Use a screwdriver to remove the screws and pull off the drain screen. Set these aside.
Unscrew the strainer body using a pair of channel lock pliers or a long standard screwdriver as leverage. Twist in a counter-clockwise motion for removal.
Remove the drain body from beneath the drain. This may require working at basement level or within the confines of a crawl space. Cut the PVC drainpipe with a hacksaw about 3 inches below the drain body. Reinstallation will require adding a PVC collar to the top of the drainpipe before adding a new drain body.
Unscrew the top drain flange using a pair of channel lock pliers. Loosen and remove by turning counter-clockwise.
Remove the rubber gasket that sits beneath the tub drain hole. A long standard screwdriver will dislodge it enough to pull it up and out of the drain.
Turn the locknut counter-clockwise to release the drain body. This is located between the drain body and the drainpipe beneath the shower pan. Pull the drain body free of the pipe.
Determine the exact location of the shower drain plumbing before starting this project. It may require partial removal of Sheetrock or, in extreme cases, the shower pan may have to be cut away to access the drain, and replaced.
A basic understanding of how plumbing works is a prerequisite for this project. An excellent tutorial on plumbing is located at Hometips.com.