The bathtub drain and stopper assembly make it possible for you to have that relaxing hot bath at the end of a hard day. A leaking bathtub drain allows water to escape, preventing that relaxing bath and, worse, causing water damage to your home. Bathtub drain leaks are often the result of an improperly sealed drain flange. You can stop a leaking bathtub drain by disassembling the old one and resealing it with a modern, durable material such as caulk.
Remove the bathtub stopper. The two main types of stoppers that operate in a bathtub drain are the lift and turn and the toe tap type. The other main type of stopper, the plunger, is located further down the drain tube and doesn't need to be removed if you are trying to stop a leaking bathtub drain. Remove the toe tap type by pulling the drain plug straight up. Rotate the plug counter-clockwise to unscrew it from the drain flange. Remove the lift and turn type by opening the drain and turning to lock it shut. Hold the bottom portion steady with a pair of pliers while removing the smaller round knob on top counter-clockwise with another pair of pliers. Pull out the larger stopper after the handle is removed.
Unscrew the bathtub drain flange. Rent or purchase a tool called a bathtub flange removal tool to make the job easier. These slip into the drain and lock onto the slots in the drain that support the stopper. Turn the removal tool counter-clockwise to unscrew the flange.
Clean off the flange opening in the bottom of the bathtub with a putty knife. Scrape away any old traces of caulk or putty. Clean the area with a bathroom cleaner and rags.
Turn the new bathtub flange over. Insert the silicone caulk into the caulk gun. Trim off the end at the 1/4-inch mark with the knife. Squeeze out a bead of caulk along the underside of the flange.
Turn the flange right-side-up. Insert it into the flange opening and thread it into the bathtub drain pipe. Use the flange removal tool to tighten.
Replace the drain stopper. Allow the caulk to dry and trim away any excess with a knife.