The drain in your bathtub closes to allow you to hold water in the tub, such as for a bath or washing clothes. The problem arises when you have a bathtub drain that refuses to close. You can fix the two main type of bathtub drains, the plug type and the lift and turn type, yourself. Disassembling the plug type is required in order to service the parts inside. A tool called a bathtub drain removal tool will help you service the lift and turn type.
Loosen the screws holding the overflow assembly in place. This is the metal plate on the side of the tub located just underneath the bathtub spout.
Pull the overflow assembly cover out of the tub. There will be a link leading down to the plug in a fully functional drain of this type. Reach inside the overflow tube and feel around with your fingers for the link if you do not see it attached.
Pull the plug and link out of the overflow opening.
Clean off the plug. Use a toothbrush to clear away any built up sediment or calcium deposits.
Inspect the link connecting the plug to the overflow plate. Replace the link assembly, if needed.
Coat the plug with silicone grease. Apply a few drops of grease to the lever assembly on the back of the overflow tube. Insert the plug into the overflow assembly.
Replace the overflow plate. Secure with the screws.
Lift and Turn Type
Lift the drain open. Hold it in place by gripping the larger part of the drain with one pair of pliers.
Grab the metal handle on top with the other pair of pliers.
Turn the smaller handle counter-clockwise while holding the larger part of the drain steady with your other hand.
Lift the large part of the drain off of the lift rod.
Examine the pull rod assembly. Extend it to the open position and clean it off with a toothbrush. Apply silicone grease to the rod. Lift it up and down several times to ensure that it is opening correctly.
Replace the flange assembly. This is necessary if the rod mechanism no longer functions. Remove the drain by turning the flange counter-clockwise. These can be hard to remove. Many hardware and plumbing stores will rent a device called a drain removal tool.
Roll out a bead of plumber's tape. Press this into place around the underside lip of a new drain and stopper assembly.
Insert the flange into place in the tub. Tighten by turning clockwise.
Extend the center rod to the upright position by pulling it up. Place the large portion of the drain over the rod. Thread the handle into the top of the rod and screw into place clockwise.