How To Replace Kohler Flush Valve [Step By Step Guide]

Kohler has become a household name for high-quality plumbing fixtures. For homeowners who are interested in learning about how to replace a Kohler flush valve, we have put together a step-by-step guide.

Here are the steps to take when replacing a Kohler flush valve:

1. Turn the water supply off. 2. Remove the flapper. 3. Press the flush valve assembly and slowly rotate it counterclockwise to loosen it. You should be able to remove it easily. 4. If the flush valve assembly has been around for quite a while then you may find some resistance when removing it. If you're stuck in this situation, just straddle the toilet backward, grab the flush valve assembly, and rotate it. 5. Once you have the old flush valve assembly removed, you're now ready to install the replacement valve. 6. Remove the flapper and the gasket of the new flush valve assembly. Lubricate the gasket with olive oil on both sides. Put it back on. 7. The flush valve assembly is a three-pronged component that fits into the bottom of the toilet tank. Position the valve in such a way that each of the prongs would go into each side of the rounded-triangle hole at the bottom of the toilet tank. 8. Once you have positioned the valve correctly, push and twist it clockwise to lock the flush valve assembly in place. The prongs serve as a lock mechanism. 9. Put the flapper back on the valve and turn the water supply back on.

Kohler flush valves are model-specific. This means that the valve may not be compatible with other Kohler toilets. Therefore, it's crucial to know where to find your toilet's model number so you can get the right parts replacement number that works for your specific toilet. Keep reading as we show you how to exactly do that!

What Causes Flush Valves To Fail? 

Inside water tank of toilet with float raised

The last thing you want is for your toilet to suddenly start flushing when you're not there. You might think it's ghosts or something else unexplainable when in fact it's just a mechanical issue that needs to be addressed.

In fact, the most common cause of toilet flushing by itself is due to the failure of a flush valve. Typically, toilet flush valves fail because of wear and tear. Here are some of the most common causes of flush valve failure. 

Worn gasket

The most common cause of why a flush valve fails is a worn gasket. Gaskets are always the first thing to wear out on anything that needs a seal. They are designed to be replaced when they become worn.

However, you're better off replacing the entire flush valve assembly. Flush valve replacement kits are available at dirt-cheap prices from most parts vendors.

For a couple of dollars more, you can find a complete flush valve assembly replacement kit with all of the necessary parts included brand new.

Worn flapper

The main purpose of a flapper in your toilet flushing system is to open and close the water path as the water level rises and falls in the tank.

When the water level reaches a predetermined level, the flapper opens and allows water to flow into the bowl when you push the flush lever to flush the toilet.

Once the water level drops below a certain level, the flapper closes the water path and stops the flow of water into the bowl. Unfortunately, the flapper can also wear out over time and become damaged. This will cause the flapper to leak and eventually fail.

Here's a video demonstrating how to replace your Kohler toilet flush valve:

Where To Find Your Kohler's Toilet Model Number?

Hand is fixing a toilet cistern at home, How To Replace Kohler Flush Valve [Step By Step Guide]

You may be wondering where to find your toilet model number and other information about your Kohler's toilet. There are a few places you can look to find them.

Firstly, you can find your Kohler's toilet model number somewhere on the tank wall. Just remove the lid of the tank and you will see this number stamped on the tank wall. Secondly, you can also find the toilet model number on your Kohler's warranty information card. 

Other places where you can find Kohler's toilet model number are the following:

  • Product packaging
  • Specification sheets
  • Invoices and receipts
  • Installation instructions

It's important to know your toilet's model number so you can get the right parts for your toilet. Some parts may not fit certain models, so it's best to know the model number before ordering any parts.

Kohler has made it convenient for its customers to find replacement parts by providing a link on their website. Just enter the toilet's model number in the search query box and you will be directed to the correct part page.

Here is the link:

Check out this Kohler genuine flush valve kit on Amazon.

What is the Difference Between a Toilet Flush Valve And a Fill Valve?

A worker is inserting the toilet flushing valve into the built-in tank. Top view.

A toilet fill valve is a device that fills your toilet tank as you flush the toilet. On the other hand, a toilet flush valve is a device that releases the water stored in your toilet tank. This releases the water in your toilet tank so you can flush the toilet.

Are Toilet Flush Valves Interchangeable?

Although there is a possibility that toilet flush valves manufactured by different brands other than Kohler can be used with Kohler toilets, some have experienced compatibility issues when the flush valve was changed to another brand. 

There will be times when you might have trouble finding the correct replacement flush valve to use due to it being unavailable. You can always check the specification sheet of your toilet for the dimensions and compare if a flush valve is a compatible fit with the tank you own.

Is There a Standard Size for Flush Valves?

When looking to purchase a new toilet flush valve, it can be helpful to determine whether the toilet is standard or dual flush. On top of this, many homeowners are wondering if the toilet flush valves are standard size. After all, what would be the point of having a standard-size toilet if the valves are not all the same size?

If you are looking to buy a replacement valve, we recommend that you go with 2 inches because it is the most common size and will work, theoretically, with any brand of toilet.

Hand is fixing a toilet cistern at home

Warning Signs of a Broken Flush Valve

The clearest sign of a broken flush valve is when it is stuck in the open position. This will cause water to continuously flow into the toilet. The water will then continue to run into the toilet bowl until the supply of water is exhausted.

A bad flapper can also cause this to occur. A faulty flapper will not properly seal the seat where the flapper sits, causing the water to leak past the flapper and into the toilet bowl. This leakage can be so severe that it causes flooding to the floor. 

You can try to troubleshoot the issue by isolating the problem area and trying to determine which component has malfunctioned. 

Can a Flush Valve Get Stuck in the Closed Position?

Yes, it can. If you notice that the flush lever has lost its tension, then it's most likely that the chain is not pulling the flapper up. Check if the chain is still connected to the flapper and if it is, check to see if there is any slack in the chain.

Additionally, if you notice that the chain is dragging on the flush lever, then make sure that the chain is not too long and that it is in good condition.

If the chain is still attached to the flapper and there is no slack in the chain, then it's possible that the joints that hold the flapper to the base of the flush valve are broken. You can try to tighten the joints or replace them. 

How To Test For Toilet Flush Valve Leaks

Testing for toilet flush valve leaks is simple, and you don't need any special tools. If you have a leaking toilet flush valve, it may not be obvious that there is a problem, so make sure you do the following: 

  • Add a few drops of food coloring to the toilet tank
  • Wait for a maximum of half an hour
  • Check the toilet bowl if any dyed water has come through
  • If the answer is in the affirmative, then you have a leaky flush valve

How Much Will It Cost Me To Replace a Toilet Flush Valve?

Flush pump for toilet cistern or drain tank

The cost of a toilet flushing valve can vary greatly depending on the specific model you choose. This depends on the manufacturer, brand, and style. However, when it comes down to it, the average cost for a Kohler toilet flush valve is around $20 excluding labor costs. 

In Closing

Replacing a toilet flush valve is easy and can be done in a few minutes. In order to properly do this you'll need to be familiar with what to look for, what to expect, and what you're doing during the process.

In addition, you should have a good idea by now of where to find the model number on your toilet. Now that you have this info, you can visit Kohler's website at and search for your toilet model number. You can then use that number to find the replacement part number that is compatible with your toilet.

You might also like:

Do Toilets Lose Flushing Power Over Time? [And How To Increase Flush Pressure!]

How To Fix A Cracked Toilet Tank, Bowl, Or Base [A Complete Guide]

How To Find The Model Number On A Kohler Toilet

Leave a Reply

Your email address will not be published. Required fields are marked *