Steps:1. Turn off water at the main. If you turn it off at the valve behind the toilet, it may fatigue the joint.
2. Drain water from the tank by flushing. Investigate for possible problems with working parts in tank. In this case there was damage on the bottom of the flapper and corrosion on the arm.
3. Scrub away any sediment or build-up on the flush arm with a brass bristled brush (figure A). Once clean, lubricate the joint between the arm and the flush handle with plumbers grease (figure B).
4. Unhook chain from handle and unclip the overflow tube. Unsnap and slide it up over the tube to remove damaged flapper (figure C).
5. Clean away all decaying material so that new flapper will operate smoothly and seat tightly.
6. Put grease on the flapper hinge and valve opening so the new flapper doesn't stick open (figure D). Also rub grease around the valve opening to ensure a tight seal.
7. Install a new flapper. An adjustable flapper has settings that can be used to vary the water flow (figure E).
8. Slip new flapper into place (figure F).
9. Hook the chain back up to the flush arm and check to make sure that it appears to be working correctly. Turn water back on.