How to Change a Toilet Tank Flapper to Fix a Continuously Running Toilet

Changing the flapper in a toilet is the last of a three-part series about fixing a continuously running toilet. In the first article we discussed reasons a toilet continuously runs and basic toilet fill valve assembly and float adjustments. In part two we discussed replacing the toilet fill valve assembly.

In this last article we will discuss how changing the flapper in a toilet tank can solve the problem of a toilet that is always running.

The toilet bowl flapper seal

Toilets operate on the principle that things in a toilet flow downhill when flushed. The water that’s in your toilet holding tank and toilet bowl are connected to a pipe that travels downhill to your local sewer system or septic. In fact, all your home’s drains operate on the same gravity principle.

What keeps the water at bay in all these systems are the valves and seals that close off the openings between the water flow and, well, everywhere else water will want to go.  This flow control system is the basis of home plumbing. It’s an idea that’s been around a very long time going back to the Roman empire.

The toilet bowl flapper seal is a great example of how this all comes together because it’s a very simple visual of how seals start and stop water flow.

The toilet chain and handle

Lifting the lid off your toilet tank you’ll see the handle is attached to a chain. The chain goes down through the water to the bottom of the tank where it attaches to the toilet flapper seal. When you operate the handle or push the button if that’s the style you have, the chain lifts on the top of the toilet flapper. 

When the toilet flapper lifts, the water can flow from the tank to the bowl through the hole the toilet flapper had been sealing. You can release the toilet chain and handle and the flapper will remain open while the water flows.

The toilet flapper itself is designed to float there in the water on its hinges while the water level goes down. After the water goes down, the flapper rest on the opening at the bottom of the toilet tank. This is what creates the seal holding the water in the toilet tank until the next flush.

The toilet flapper assembly

Looking at the toilet flapper assembly you’ll notice it is connected by two tangs that are part of a tube. The tube is the toilet fill tube, and the tangs are the hinges we talked about earlier.

The toilet flapper itself is made of rubber. When you look at it, you’ll see there’s a bell shape to the bottom and usually a hole on the top by where the chain connects. There are also two arm type connections with holes in them. These holes are where the tangs of the fill tube go through creating the hinge effect for the toilet flapper assembly to move on.

This very simple system of the toilet flapper and toilet chain and handle is an example of human ingenuity at work. The concept’s been around for thousands of years. When you humbly replace the rubber flapper in a toilet tank, you are part of the ongoing evolution of human engineering. Congratulate yourself!

Ten steps to replace the rubber flapper in a toilet tank

  • Step one: Turn off the water flow at the wall valve.
  • Step two: Lift the toilet tank lid being careful to set it somewhere where it won’t scratch or chip.
  • Step three: Flush the toilet. Note: You won’t need to make sure the bottom of the tank is entirely dry when you’re changing the flapper in a toilet tank. Removing the water from the tank just makes it easier for you to work.
  • Step four: Disconnect the chain from the lift handle assembly. Note: Your new flapper should have a new chain with it. While it’s always a good idea to use the new parts, you don’t have too. You can simply remove the chain connection from the toilet flapper and reuse the existing chain.
  • Step five: Gently pry the toilet flapper arms from the tangs at the base of the fill tube. Note: You should not have to use any tools to pry the flapper from the tangs. Unless you absolutely must use a screwdriver to wedge the arms off, use your hands to the best of your ability.
  • Step six: In a reverse fashion, attach the arms of the new toilet flapper to the tangs of the fill tube.
  • Step seven: Attach the lift chain to the flapper or to the handle lift arm depending if you used the existing chain or are using the new chain.
  • Step eight: Turn on the water at the wall valve.
  • Step nine: Let the water fill. At this point the flapper should be completely seated on the bottom hole of the tank allowing the water to fill the tank. If it’s not, you must adjust where the chain attaches to the lift lever to allow the toilet flapper to seal.
  • Step ten: Check for flush and put the tank lid back on. Once the tank has filled, operate the handle or button to flush the toilet. If the toilet flapper chain is too loose to raise the toilet flapper, you must adjust the chain.

Changing the toilet flapper to fix a toilet flapper seal

If you’ve worked through this three-part series to stop a toilet from running constantly, your toilet should now be working fine. If It’s still giving you grief you can give Fountain Plumbing here in Tyler, Texas a call. You may need a closer look at your tank assembly.

Fountain Plumbing has been serving Tyler, Texas with honesty and integrity for years. We would like the opportunity to make you one of our valued customers. Give us a call to find out more about how to fix a constantly running toilet, or any of the other plumbing projects you have around your home.

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