It’s easy to remove a tub stopper to check it for mechanical problems or blockage. You’ll encounter a couple of different types of bathtub pop-ups: old-style mechanisms like the one shown in our below illustration, and newer spring-loaded pop-ups.
For an old-style pop-up:
1.Simply grip the stopper body and pull it out of the drain along with the hinged rocker arm.
2. Clear the stopper and rocker arm of hair and debris.
3. Check the rubber seal for damage and, if necessary, replace it. Remove the old seal and slip on a new one if needed.
4. Reinstall the stopper and rocker arm. Make sure the flange is tightly seated and in good shape. (Older tubs may have corroded flanges.)