Toilet Gasket Replacement In 3 Ways

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Last Updated on August 29, 2022 by acechapman

Do you notice a leaky toilet bowl? Most likely, the problem is with the toilet tank-to-bowl gasket. Also known as a “spud washer”, this post will show you how toilet gasket replacement in a simple and straightforward manner.

The toilet tank-to-bowl gasket seals water from the tank through the flush valve to the bowl. It is made of rubber and allows for no leakage. The problem is most likely with the gasket. Therefore, it is necessary to replace it if water starts leaking from the bowl and tank after flushing.

Replacing The Toilet Tank Gasket

  • The removal of the toilet tank
  • Gasket replacement and purchase
  • Installation of the toilet tank

Although flush valves come in different sizes, the universal toilet tank-to-bow gaskets can be used for all types of toilets. Most flush valves are 2 inches in diameter, but some toilets have flush valves that measure 3 to 4 inches.

First, determine the size of your flush hose. This will allow you to determine the size of tank-to-bowl gasket that you need.

To replace the toilet tank to bowl gasket turn off the water supply to the toilet. Flush the toilet and take out the toilet tank. Then, slide the new gasket in and remove the old one. Turn the water on and install the tank. Check for leaks.

Materials Needed:

  • Flathead long screwdriver
  • Adjustable wrench
  • Old towel/rag
  • Gasket changed
  • Optional bolts and washers
  • Sponge
  • Bucket

It is always a good idea to replace the tank bolts or washers when replacing the toilet bowl gasket. The toilet tank bolts can become corroded over time and will then need replacement.

Two washers are used to back up the bolts and nuts. There are two types of washers: a metallic one and a rubber one. The rubber washer should always come in direct contact with the tank. This is to ensure that the tank does not crack if you tighten it too much during installation.

Rubber washers prevent the toilet from leaking around the bolts. These washers tend to wear down due to hard water minerals in the toilet tank water. Therefore, it is important to replace them.

toilet gasket replacement

Steps For Toilet Gasket Replacement

Once you have all of the necessary items, it’s time to get to work. You can also replace all of the parts in your toilet tank while you are doing this repair.

It is better to replace the entire tank than one component at a time. You will then see a better flushing toilet if you replace all of the parts.

This is also a good time to paint the tank’s back. People are always wanting to paint the toilet tank but they don’t have the time. Now is the perfect time to do it since the toilet tank is set aside for a while.

Let’s now look at the steps to replace a toilet bowl gasket.

Remove The Toilet Tank

Usually, a toilet tank is placed above the toilet bowl. Thus, allowing for flushing easily by the force of gravity. Through the toilet fill valve, a water supply line is run from the shutoff valve to the tank.

These steps will help you to drain the toilet tank.

  • Turn off the water supply. There are two types. To prevent water from entering the tank, turn the valve clockwise. You can pull it inwards to close, and outwards to open the second type.
  • Flush the toilet. It is crucial to hold the lever down while flushing the toilet.
  • Place the lid of your toilet tank securely so it doesn’t fall off or crack.
  • Use the sponge to remove any water remaining. You should dry the toilet tank.
  • Disconnect the supply from the tank. If the coupling is too tight, always do it by hand. Bend the threads of the plastic coupling with a wrench.
  • Use the bucket to drain any remaining water in the water supply line.
  • After removing the supply line, you can use the adjustable wrench for removing the bolts from the tank.
  • If the bolt is loosening or swiveling, you can use the long screwdriver to remove the bolt from the tank. The wrench will allow you to remove the nut from beneath the tank.
  • If the above method doesn’t work, you can use a hacksaw to remove the nuts.
  • Then, after removing the bolts, lift the toilet tank off and place it upside-down on a towel or rag.
  • Take out the old gasket.

Buying And Installation Of New Toilet Gasket

After you have taken out the old gasket, clean it up and inspect it for defects. While it is not recommended to reuse or repair a gasket, there are times when the gasket wears out. In the event that the flush valve nut is damaged or needs to be replaced, make sure you check its condition.

The large nut that holds the tank-to-bowl gasket in place is called the flush valve nut. If it breaks, you’ll need to replace the whole flush valve. This is how you replace a toilet flush valve.

You can not reuse the rubber washers for the toilet tank. To avoid future repairs, it is best to purchase the complete kit including the gasket, bolts, and nuts.

You should ensure that the tank and bowl gaskets you purchase are the right size. Some may not be the same size, depending on the toilet model.

The flush valve’s size will determine the size of your toilet tank and bowl gasket for replacement. The diameter of flush valves is between 2 and 4 inches. To determine the right size gasket, measure the diameter of the flush valve.

Fluidmaster and Korky have the best universal toilet tank-to-bow gaskets and other toilet tank repair kits.

It is very easy to install the gasket once you have it ready. Simply slide it back in the same way as the previous one. Slide it all the ways and ensure it fits over the flush valve nut.

toilet gasket replacement

Installing The Toilet Tank

The arrangement of the washers is crucial when installing the toilet tank. Use rubber and metallic washers. Rubber washers should always come in direct contact with the tank.

Once you’re confident with the new gasket, install the toilet tank in the following order:

  • Insert a metal washer and a rubber washer into the bolt. Slide it through the hole in the tank’s bottom. Repeat the process for the second bolt.
  • Cover the protruding ends at the bottom of each tank with a rubber washer.
  • Tighten each bolt against the washers by screwing in a new nut.
  • Then, remove the nut using a wrench. Repeat the process for the second bolt. You should not tighten the bolt too tightly as this could cause cracking in your toilet tank.
  • Fix the toilet tank on top of your toilet bowl by lifting it up. The two bolts will be guided through the holes in the toilet bowl.
  • Continue to feed the washers, nuts, and bolts as before.
  • Hold both nuts in place until you reach the washers.
  • Tighten the nuts with your wrench, but not enough to cause damage to the toilet. To keep the tank in place, tighten the bolts alternately.
  • Connect the water supply line back to the tank.
  • Reattach the lid to your toilet tank.
  • Then, turn on the water shutoff valve to let water flow into the tank.
  • Check the tank for leakages between the bowl and toilet tank.
  • Now, you finally know how to change a toilet bowl gasket.

There is a possibility that the flapper fell out of its place while in the process of toilet gasket replacement. So, make sure that the water inlet valve is properly aligned with the flush valve opening before you open it.

Frequently Asked Questions

What is causing my toilet to leak from the bottom of the tank?

The rubber gasket connecting the tank to the bowl has worn out or been damaged. The rubber seal stops flush water from leaking at the joint of the tank and the bowl. It will need replacement.

How can I fix a leaky toilet tank bolt?

Toilet tanks are mounted using bolts that are backed up with rubber washers. Rubber washers serve two purposes. Rubber washers prevent water from getting through the bolt holes. They also prevent the tank from breaking during installation. You will need to tighten or replace the washers and bolts if they are loose or worn.


A leaking toilet is something that most people will experience at one time or another in their lives. The first step to fixing the problem is to identify the source of the leakage. Most people can’t fix this problem themselves, so they pay large sums of money to have them fixed by a plumber. You can save a lot of money if you are able to learn the steps for toilet gasket replacement, as well as other repairs.

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