Delta manufactures a number of pop-up drain assemblies, but the basic design of each assembly is the same. Attached to the back of the assembly's cover plate is a linkage. Attached to the bottom of the linkage is a cylindrical-shaped drain stopper. When the trip lever is engaged, the tub fills with water because the stopper has closed off the drain pipe. It is for this reason that a broken stopper will cause the tub to slowly lose water. Replacement Delta stoppers are available, but the existing stopper must first be removed.
Things You'll Need
Actuate the pop-up drain's trip lever to lift the stopper out of the drain pipe.
Remove the screws that secure the cover plate assembly to the bathtub's wall, using the screwdriver.
Pull the cover plate assembly out of the tub. The linkage and drain stopper will slide out of the opening as the plate is removed.
Pull the pin securing the stopper to the end of the linkage out of the stopper with pliers. This will release the drain stopper.