The bathtub drain trap is located at the base of the tub just below the faucet, where the water drains out of the tub. Some traps contain a stopper, which stops water from leaving the tub, allowing you to take a leisurely bath without worrying about the water level. Occasionally, these traps will rust or buckle, resulting in leaks and less than optimal water-stopping ability. When this happens, you'll need to repair your bathtub drain trap.
Remove the drain stopper if present. The two most common types of stopper that might be attached to a drain trap are the twist and lock type and the toe tap type. The twist and lock type can be identified by the small cap on top of the stopper. To remove these types of stoppers, twist the top cap off in a counterclockwise direction. Lift the stopper out. The toe tap type of stopper is removed by turning counterclockwise. Set the stopper aside.
Insert a pair of pliers into the drain and grab the tines at the bottom. Remove the drain trap by twisting the drain counterclockwise. If this proves difficult, you can rent or purchase a drain trap remover from your local hardware or plumbing store. This tool is specially built for twisting out hard to move drain traps.
Clean out the tub area around the drain trap. Remove any rust spots with a rust remover. Scrape away any old putty or caulk with a putty knife.
Turn the new drain trap over so it is upside down. Place a thin strip of plumber's putty along the diameter of the drain. The easiest way to do this is to roll it into a thin strand and then press it into place.
Turn the drain trap right side up. Twist it into the drain opening. Use the pliers or removal tool to tighten the drain in place.
Replace the stopper by inserting it into the drain and turning clockwise.
If you are repairing an older drain that is rusted in place, you can cut it out with a rotary type Dremel tool. Silicone caulk is an alternative to plumber's putty.