How to Remove and Replace a Bathtub Drain Flange

Before starting, ensure the work area is clean, dry, and prepared. Lay an old towel or thick cloth in the bottom of the bathtub to prevent any accidental scratches or damage from dropped tools. Gather all necessary tools and materials and have them within easy reach. It can also be helpful to temporarily block the overflow opening with a rag to prevent screws or small parts from falling down into the drain system.

For a twist-and-turn stopper, first, open the stopper to the up position. Unscrew the small knob on the very top by turning it counter-clockwise. Once the knob is off, you may see a brass post with a slot for a flathead screwdriver or a small set screw on the side. If there's a set screw, use the appropriate screwdriver to loosen it. If it has a slot on top, hold the main body of the stopper and unscrew the center post counter-clockwise. Once loose, lift the entire stopper mechanism out of the drain.

With the stopper removed, you will see the metal cross-pieces inside the drain. Insert the drain wrench (also known as a dumbbell wrench) so it firmly engages these cross-pieces. Fit the handle of a large adjustable wrench or a large screwdriver through the top of the drain wrench to use as a lever. Apply steady, firm pressure, turning counter-clockwise to unscrew the drain flange from the drain shoe below. This may require significant force if the flange is old and sealed tightly.

Once the old flange is removed, you will likely see a ring of old, hardened plumber's putty and other residue around the drain opening on the tub surface. Use a plastic putty knife to carefully scrape away all of this old material. Then, use a rag dampened with denatured alcohol or a mild solvent to thoroughly clean the surface where the new flange will sit. Also, use a separate rag to clean the female threads inside the drain shoe below. A clean surface and clean threads are critical for a proper, leak-free seal.

Take a generous amount of plumber's putty and warm it in your hands by kneading it. Roll it into a uniform rope about 1/4 to 3/8 inch thick. Press this rope of putty firmly onto the underside of the lip of the new drain flange, forming a complete circle. For an extra layer of protection against leaks, wrap the male threads of the new flange with 2-3 layers of thread sealant tape in a clockwise direction (the same direction you will tighten it).

Your new drain kit should include a thick rubber gasket. This gasket goes between the underside of the bathtub and the top of the drain shoe. From the top, carefully screw the new, prepared flange into the drain shoe, turning clockwise. Be careful not to cross-thread it. Hand-tighten it as much as possible. Then, insert the drain wrench and use your lever to tighten it another quarter to half turn until it is snug. You should see an even ring of plumber's putty squeeze out from under the flange lip. Use your finger or a soft cloth to wipe away this excess putty for a clean finish.

Reinstall the tub stopper mechanism by reversing the steps you took to remove it. Screw the central post back into the cross-piece, then attach the top knob. Before using the shower, perform a leak test. Close the newly installed stopper and fill the tub with a few inches of water. Let it sit for 10-15 minutes and check for any signs of leaks around the drain (if you have access below) or simply observe if the water level in the tub has dropped. Then, open the stopper and let the tub drain completely, again checking for any leaks while the water is flowing.