How to Replace a Bathtub Drain Assembly

When to Replace a Bathtub Drain

Bathtub drain assemblies should be replaced when the drain flange is corroded, cracked, or no longer seals properly against the tub surface. Chronic slow draining that persists after cleaning and snaking may also indicate a corroded or rough interior that traps debris. Replacement is also necessary when switching drain styles, such as from a trip-lever to a lift-and-turn stopper.

Removing the Old Drain

Remove the existing stopper mechanism according to its type. For the drain flange (the visible metal ring in the tub floor), insert a drain removal tool into the crosshairs and turn counterclockwise. If the flange is stuck, apply penetrating oil and wait 15 minutes before trying again. Some older drains require a special dumbbell-shaped removal tool. Once loosened, unscrew the flange completely and clean all old putty from the tub surface.

Installing the New Drain

Inspect the drain shoe (the elbow-shaped fitting beneath the tub) and replace it if corroded. Apply a generous bead of plumber's putty around the underside of the new drain flange. Thread the flange into the drain shoe by hand, then tighten with the drain tool until the putty squeezes out evenly around the flange. Wipe away excess putty with a rag. Install the new stopper mechanism according to the manufacturer's instructions.

Testing and Final Adjustments

Close the new stopper and fill the tub with several inches of water. Let it sit for 30 minutes, then check beneath the tub for leaks at the drain shoe connection. Open the stopper and verify water drains quickly without gurgling. If the stopper does not hold water, adjust the linkage length or the stopper position. For trip-lever assemblies, adjust the threaded rod to raise or lower the plunger for a proper seal.