How to Install a Stopper Drain Fitting in a Bathtub

Blue bathtub and drain with green towel and white curtains

Glasshouse Images / Getty Images

Overview
  • Working Time: 15 - 25 mins
  • Total Time: 15 - 25 mins
  • Skill Level: Beginner
  • Estimated Cost: $30 to $50

A tub drain with a built-in pop-up stopper has distinct advantages. This type of stopper, which operates by hand or foot, is more durable and easier to maintain than pop-up stoppers that operate by a trip lever and linkage running through the overflow tube. And if you have an old-style tub with a rubber stopper held by a chain, a stopper drain fitting will modernize your fixture. 

Drain converter kits come with a threaded drain fitting with a built-in stopper plug, plus a blank cover for the overflow opening to replace the trip-lever cover plate used with the old stopper assembly. Several styles are available, some of which use a spring-loaded stopper that closes and opens with a simple push of the toe, and others with grip knobs that are opened and closed by lifting or lowering by hand.

Before You Begin

If you don't already own one, spend a few dollars on a tub drain wrench, often known as a dumbbell tool. This specialty tool makes quick work of the otherwise difficult task of unscrewing the upper drain flange fitting from the drain shoe fitting below the tub. Tub drain wrenches usually have two ends for different sizes of drain openings. The end inserts into the opening with the keys fitting into the crosshairs of the drain strainer. Then you turn the tool with pliers to loosen the drain fitting. If your drain doesn't have crosshairs, you need a variation on the drain wrench called a drain extractor.

Also, be sure to get the right size of drain fitting for your drain shoe fitting. If you're not sure of the size of your tub drain, you can buy a kit that can be adapted to two drain sizes.

A tub shoe kit and dumbell wrench
Aaron Stickley

What You'll Need

Equipment / Tools

  • Screwdriver
  • Tub drain wrench (dumbbell tool)
  • Channel-type pliers or adjustable wrench
  • Putty knife

Materials

  • Tub drain converter kit for a stopper drain
  • Plumber's putty
  • Non-scratch scouring pad

Instructions

  1. Remove the Old Stopper and Linkage

    If you are replacing a traditional lever-operated stopper, unscrew the cover plate on the over-flow opening and carefully extract the stopper's level rod and linkage from the opening. Immediately replace the overflow cover with the blank cover provided by the new stopper kit.

  2. Remove the Old Bathtub Drain Fitting

    Use the tub drain wrench to remove the existing drain fitting from the drain shoe. (Some tubs may have a strainer grid that first needs to be removed before you can assess the drain fitting.) First, determine which end of the wrench will fit inside the drain opening and around the drain fitting's crosshairs. Insert the wrench into the tub drain and align it with the crosshairs, then use channel-type pliers or an adjustable wrench to rotate the drain fitting counterclockwise and loosen the fitting. It will unthread from the tub shoe below the tub. Keep turning until the fitting comes free.

    Dumbell wrench removing a tub shoe
    Aaron Stickley
  3. Clean the Tub Drain Opening

    Pull the fitting from the tub, and clean off the ring of plumber’s putty that surrounds the opening of the tub drain. It is best to have a clean surface to work with, so be sure to remove as much of the putty as possible. If the plumber’s putty is dried in place, you can use a non-scratch scouring pad to remove it.

    Clean putty off of drain opening
    Aaron Stickley
  4. Determine the Drain Thread Size

    Use the old fitting to determine the size of your drain. A bathtub drain converter kit often provides drain threads in two sizes to accommodate different tub drains. Select the appropriate thread attachment.

    Tub Shoe Threads
    Aaron Stickley
  5. Install the New Drain Fitting

    Remove the tub stopper from the new drain fitting—often this is a matter of simply unscrewing it. Apply a generous band of plumber’s putty to the bottom of the flange on the new fitting. Insert the fitting into the bathtub drain opening, making sure to center it.

    Make sure to thread the fitting into the shoe carefully. A good way to avoid cross-threading is to start tightening by hand first. When it looks like the fitting's threads are screwing properly into the drain shoe, you can continue tightening by using the tub drain wrench.

    Lastly, clean off any excess plumber’s putty from around the drain fitting, then insert the stopper and test the drain.

    Install a new tub shoe
    Aaron Stickley