The valves and flushing assembly in a toilet don’t last forever, and sometimes parts need replacing.  A plumber will typically charge around $100 to fix a leaking toilet.  But this is a job that any reasonably handy person can do themselves, and the parts are very inexpensive. 

If you know what particular part the problem, you can often replace it for just a few dollars.  In my case, the entire assembly was a poor design , and broke within a month of our moving in, and worked poorly even when it wasn’t broken.  So I replaced the entire assembly. 

Many of the online reviews I have read complain about the low quality of the installation instructions that come with repair kits, so I thought I would add some of my own tips to help first timers along.  A word of warning:  this process involves lifting the entire tank off the toilet, and moving it around.  The tank weighs about 30 pounds, so if that seems like a lot, be sure to have someone available to help you with the lifting.


I used the Fluidmaster complete repair kit, because I wanted to replace everything. The same kit is also available at the big home improvement stores.   This toilet was about 20 years old, so there was no point replacing one part, and then having to replace something else in a year.


Large slip-joint pliers, screwdriver, wrench or socket set, tape measure, hacksaw, bucket or pan.

1. Empty the Tank

First turn off the supply valve at the wall and then flush the toilet. The instructions that come with the kit tell you to use a sponge and towel to get all the remaining water out of the tank.  You do not need to waste your time doing this, as you’ll see below.

2. Remove the Handle and Lever

Take the lid off the tank, and remove flush handle and lever by unscrewing the nut inside the tank.  It is very important to note that this is a left hand threaded nut; in other words, this one is ‘righty-loosey.’

3. Remove the Fill Valve

First put a bucket or pan underneath the fill valve, where the supply line enters the bottom of the tank.  This is why you don’t need to sponge the water out of tank, because it’s going to come out of this hole into your bucket, which is much easier.  Unscrew the small nut that connects the supply line to the fill valve, and then unscrew the large nut that holds the fill valve to the inside of the tank.  Disconnect the plastic tubing that goes to the flush valve, and then remove the entire fill valve assembly.

Toilet Tank Removed
Credit: Gibbon

4. Remove the Tank

You need to remove the entire tank from the toilet to replace the flush valve.  The tank is held to the toilet bowl with either 2 or 3 bolts.  You will need to remove the nuts on these bolts from underneath the rear of the toilet bowl. 

On my older toilet, the bolts stuck in place well enough that they did not turn as I undid the nuts.  However if you find that the bolts themselves are turning, you’ll need a long screwdriver to keep the bolts stationary.  It is possible to do this yourself, but is easier with a helper.  A ratcheting wrench really helps here, because there is not much room to turn a standard crescent wrench under the toilet.  Depending on how long your existing bolts are, you may need deep sockets, also. Once the nuts are off, lift the toilet tank straight up, and place it on its back on a soft surface such as an old towel or rug.

5. Remove the Flush Valve

First remove the soft gasket that sealed the tank to the bowl.  Once the gasket is gone, you can get to the large nut that holds the flush valve.  This is where you’ll need the large slip joint pliers.  Once the nut is off, the entire flush vale will lift out of the tank.

Flush Valve Cut to Length
Credit: Gibbon

6. Cut the Flush Tube to Length

The new flush tube will be extra-long, and must be cut to the proper length.  First, place the flush valve assembly into the tank and mark the tube at the correct height according to the included instructions.  Then remove the tube and cut it with a hack saw.  Clean up the cut end with some sandpaper or a knife.

7. Install the New Flush Valve

Place the flush valve back in the tank, secure it with the large nut, and install the new gasket over the nut.  Note that if you have a Gerber toilet, the included gasket will be too small, and you will need to buy a larger one.

8. Reinstall the Tank

Depending on how your bolts were originally installed, you will likely want to insert the supplied bolts and gaskets in the tank, then install washers and nuts outside the tank, and then place the tank back in place on the bowl.  Then put the washers and nuts on from below the bowl.  Again, you may need a long socket, and possibly a screwdriver in the tank to keep the bolts from turning.

9. Install the New Fill Valve

Place the fill valve in the tank, and orient it to face the flush valve.  Install the large nut outside the tank to secure the fill valve, and connect the supplied tubing from the fill valve to the flush valve.  Then re-attach the water supply line to the tank.

10. Adjust the Chain Length

Connect the chain from the flush handle to the flapper valve.  It is very important  to cut off any extra length of chain.  Too much extra chain can get caught in the flapper and cause the toilet to run-on and waste water. I've learned this the annoying way.

You’re done!  Turn the water supply back on, give the toilet a couple of test flushes, and then give yourself a high-five!