How to Fix the Flapper on a Running Toilet

Google+ Pinterest LinkedIn Tumblr +

Take the tank lid off and look inside, you will see what is called a “flapper.” When you push down the flush handle, the flapper is pulled up and a hole in the bottom of the tank is visible. That’s where the water goes. If the flapper is corroded or there is hard water buildup on the hole it closes, it will not seal properly. This will cause a slow leak of water from the tank, and when the level is low enough the tank will refill.

 Things You’ll Need:

  • New Flapper
  • Scissors
  • Rubber Gloves

 Turn off the water supply to the toilet. The turn-off valve is usually directly under the tank.

 Lift the top of the tank. Careful. It’s porcelain, and if you drop it, it will probably break.

 Flush the toilet so you have very little water to contend with.

 Put on your rubber gloves, if you haven’t already. Remove the old flapper. Sometimes this is as simple as just picking it up. If it’s that simple, then it’s way past time to change it. The one I changed was so corroded it felt like sticky jelly.

 Remove the new flapper from the packaging. Read the instructions. Sometimes this will confuse you, but it’s always a good idea to read them.

 Insert the serrated strap (supplied with the new flapper) into the hole at the front of the new flapper. Draw the strap all the way though the slot until it “locks” into place.

 Alternative Installation Methods:

  1. For brass overflow tubes: Slide the collar over the overflow tube until it is all the way down.


 For plastic overflow tubes with integral mounting lugs: This universal replacement is set up so that you can cut along lines marked “CUT” to remove the collar. Slip ears over the prongs at base of overflow tube.

 Align the flapper bulb centered in its seat. Pull the strap through the hole in the tank lever so the flapper closes with a bit of slack in the strap. If the strap is too tight, the flapper won’t seal correctly and you will still have a running toilet. If it’s too tight, just pull the strap back a couple of notches. I did this the first time.

 Be careful when pulling the strap through the hole in the tank lever, because these levers break easily, especially if they’re old.

 Turn the water back on and check for leaks.


 There are several kinds of flappers. The “universal” replacement is set up for a couple of different kinds of arrangements. 


About Author

Leave A Reply