How to Replace a Pop-up Bathtub Drain and Overflow Assembly

Begin by removing the two screws holding the overflow plate to the tub wall. Once the screws are out, gently pull the plate away from the tub. The trip-lever and the connected linkage assembly will come out with it. Carefully pull the entire linkage mechanism up and out of the overflow pipe. Place the old plate, screws, and linkage aside.

The drain flange is the metal ring inside the tub at the bottom. It is threaded into the drain shoe below the tub. To remove it, insert a drain key (also called a drain wrench or dumbbell wrench) into the crossbars of the drain. Turn the wrench counter-clockwise with a pair of channel-lock pliers or an adjustable wrench to unthread and remove the flange. If it's very stubborn, you can try inserting the handles of the channel-lock pliers into the drain crossbars and using a screwdriver as a lever to turn them.

Locate and open the plumbing access panel, which is typically on the wall behind the faucet end of the tub. Using a flashlight, identify the waste and overflow assembly. It consists of the vertical overflow tube connected to the overflow opening and the drain shoe connected to the tub drain, which join at a sanitary tee. Use channel-lock pliers to loosen the two large slip nuts: one connecting the overflow tube to the tee, and one connecting the drain shoe to the tee. You may need a bucket to catch a small amount of residual water.

Once the slip nuts are disconnected and the drain flange is removed, the entire waste and overflow assembly is free. Carefully maneuver it out from behind the tub through the access panel opening. Take the old assembly and compare it to your new kit. Lay the new parts out next to the old ones. You may need to cut the new plastic pipes to match the length of the old ones. Use a hacksaw or a tubing cutter for this. Dry-fit the new assembly (without gaskets or putty) to ensure all lengths and angles are correct before proceeding.

Thoroughly clean the tub's drain opening and overflow opening with a rag, removing all old plumber's putty and residue. Take a small amount of new plumber's putty and roll it into a snake-like rope about 1/4 inch thick. Press this rope firmly onto the underside of the new drain flange's lip. From inside the access panel, hold the new drain shoe assembly (with its rubber gasket) up against the underside of the tub's drain hole. From inside the tub, carefully thread the new putty-lined drain flange into the drain shoe. Tighten it using your drain key until it is snug and putty squeezes out. Do not overtighten. Clean up the excess putty with a rag.

Now, connect the rest of the assembly. Slide the thick, beveled overflow gasket over the end of the overflow tube, ensuring the beveled side faces the tub. Push the tube against the back of the tub's overflow opening. From inside the tub, place the new overflow plate over the hole and secure it with the provided screws, which will thread into the overflow elbow, sandwiching the tub wall and creating a seal. Then, from the access panel, connect the overflow tube and the drain shoe to the sanitary tee using the new slip nuts and gaskets. Hand-tighten the nuts first, then give them a final quarter-turn with channel-lock pliers.

Insert the new stopper into the drain hole. Drop the new linkage assembly down through the overflow opening. You may need to adjust the length of the linkage rod (usually by threading it in or out of the connecting clevis) to get the correct action. Test the trip-lever on the overflow plate. When the lever is down, the stopper should be up, allowing water to drain. When the lever is up, the stopper should be down, sealing the drain. Make adjustments until it operates smoothly and seals completely.

With the access panel still open and a flashlight handy, close the drain stopper and fill the tub with several inches of water. Carefully inspect all the new connections (the drain shoe, the overflow gasket, and the sanitary tee connections) for any signs of dripping or moisture. Let the water sit for 5-10 minutes. Then, open the drain by flipping the trip-lever and let all the water drain out. As it drains, continue to watch the connections for leaks, as the pressure and flow of water can sometimes reveal issues not seen in a static test. If everything is dry, you can close up the access panel.