Turn off the water supply to the toilet using the valve next to the base of the toilet. Hold the handle on the toilet down so all the water drains from the tank.
Angie's How To Replace a Toilet Flush Valve Seal
Is your toilet running constantly, and running up your water bill in the process? This simple, inexpensive DIY job could fix the problem.
You don't need any tools. Just follow these steps to replace a toilet flush valve seal.
RELATED: Have a toilet flapper, not a flush valve seal? Here's how to replace a flapper.
Remove the lid to the tank. Inside, in many toilets, an arm called a trip lever extends from the handle used to flush the toilet to the flush valve. Unhook the trip lever from the holder that attaches it to the flush valve. Also, remove any chain attaching the two.
Gently pull the refill tube out from the stop cap atop the flush valve. Keep the tube pointed down into the tank so it doesn’t spurt any remaining water on the floor. Unscrew the stop cap. Pull the float assembly up and off the center guide post.
Remove the old seal, a ring often red in color, and discard. Position the new seal in the top groove of the flush valve.
Put the float assembly back on the center guide post. Screw on the stop cap, re-hook the trip lever and insert the refill tube into the stop cap.
Turn the water back on to the toilet. Flush. Make sure it doesn’t run continuously. Everything sealed? You’re done.