feet in front of a toilet that has a wrench and saw on top of toilet seat

Kendall "aka Renos"

Founder, Lead Instructor of Renos 4 Pros and Joes and Bathroom Update Guide

Replace Toilet Tank Bolts, especially Rusted Bolts

Whenever a toilet needs maintenance, sometimes you get lucky and can do everything without moving the tank. Other times you may get unlucky and have the joy of removing the tank. The age of the toilet components, as well as water conditions, can factor into how easy the bolts will be to remove.

Unscrew nuts from bolts

In order to remove the toilet tank bolts, you will need a flat head screwdriver and a wrench. Use the flathead screwdriver to hold the bolt in place and then seat the wrench over the nut on the underside of the tank and turn wrench counterclockwise to loosen. Do not switch the process by holding the bolt and turning the nut with the screwdriver. It will be tempting to do it, but you may be creating a problem for yourself in the future. NOW if your bolts are rusted or for some other reason can’t be removed, it’s going to take a bit more effort to remove the bolts. Below we’ll discuss your options for how to work through these problem nuts and bolts. 


Rusted tank bolts

Rusted bolts can be one of the most frustrating aspects of working on and repairing toilets. They can be a huge time killer and a drain your momentum. Stay positive and let work through it.

Before you start working with rusted bolts, or any bolts for that matter, you should have already turned off the water supply, drained the water from the bowl and soaked up as much residual water at the bottom of the bowl as possible. The reason is once you loosen the bolts at the bottom of the tank, the rusty water is going to run out on the floor, so the more water you can eliminate, the smaller mess you should make.


Now, this is where the actual fun begins. There will be times when you open the tank and the tops of the bolts are swollen and blistered. When you put the screwdriver on the head of the bolt it may appear to turn into DUST!


In this scenario, you are going to have to work a little harder to remove the bolts. You have multiple options, the solution that you chose should be based on your time, and budget, the tools you have immediate access to, and how hard you want to work.


Replace toilet tank gasket

Before we jump into the different ways to remove rusted bolts, please note that now will also be a great time to examine and replace your toilet tank gasket if necessary. The reason is that you have to remove the toilet tank bolts to access it, and since you are already replacing the bolts, you’re already replacing the bolts, you basically already more than 95% there. It will literally take you 30 more seconds to replace the toilet tank gasket, and it could save you from having to remove the toilet tank bolts in the near future in order to replace it.


Mini-Hack Saw

The mini hack saw is a manual hand tool that you operate with one hand. The blade is flexible and will allow you to slip it underneath the head of the bolt or whatever is left. If the rusted bolt fits tight against the bottom of the tank, you may have cut through the rubber washer in order to access the bolt. You can also try to strip the rubber washer out by using needle nose pliers or something similar to chip and tear away at it until you can remove enough of it to place you hack saw blade against the stem of the bolt. Once you have the hacksaw in place begin moving the tool back and forth until you are able to cut through the bolt. Using a fresh hacksaw blade can save you time and effort over using a dull worn blade.


Reciprocating Saw – Sawzall

If you have access to a reciprocating saw, this method is going to be much faster than using a hacksaw. However, you will have to be more careful with the saw to ensure that you do not damage the toilet. You will need a metal blade attachment to cut through the bolt. Metal blades for reciprocating saws come in different lengths.

Some are very short  (less than 6 inches) while others are extremely long(over a foot). Some people can control the short blade better, while others prefer a long blade that the can wedge under the bolt head from a distance.

Which blade you choose will depend on the space you have in the tank and around the bolt as well as personal preference. Once you have the blade seated against the bolt start off slow so that your saw blade is under control. You don’t want the blade hitting or impacting against the inside of the porcelain tank as its cutting.


Cutting the bolt from inside the tank is the safest way to remove a rusted bolt, but if for some reason you are not able to get it done from the inside, you do have the option of trying to cut the bolt from the underside of the tank.

Depending on the construction of the toilet this may be easier to access. Take even more precaution when cutting on the exterior of the toilet tank, because if you create any cosmetic blemishes on the finish of the toilet they may be visible.


Bolt Cutters

Bolt cutters can also be the solution to removing a rusted tank bolt. You will need more space to work with the bolt cutters. The most ideal scenario to use bolt cutters would be when the nut has unscrewed enough to become loose, but won’t come off any further.

An inexpensive set of handheld bolt cutters are going to cost you more than a mini hacksaw, but far less than a reciprocating saw. The main concern is whether you can get the nose of the bolt cutters around the stem of the bolt. Once you have determined that you can, it should be relatively smooth sailing from there.


Bolt cutters work using compression strength. You will have to use your hand strength on this one and it may take both hands and multiple attempts to cut all the way through the stem on the bolt. Prepare for a hand, forearm and chest workout.


Now if by chance you have access to a set of full-size bolt cutters, and they will reach the stem of the bolt, you may be able to cut through it from the bottom of the tank. Clearance is going to be the main concern for using full-size bolt cutters. Now if the big bolt cutters will reach the bolt, cutting will be a breeze. It should cut through the bolt like butter.


Once you determine that the water is definitely coming from the tank, you have a shorter list of solutions. Tank leaks are usually caused by one of four things, a leak at the tank water supply, a leak at the tank bolts, or a leak at the gasket in the center of the tank, or a crack in the tank.

Installing new toilet tank bolts

Now that you have finally removed the old toilet tank bolts, you can install the new ones. This is pretty straight forward. However, there are a couple of rules to follow.


Number 1, once you have the nut on the bolt, be sure to screw the nut onto the bolt and do not screw the bolt in the nut. Basically, you need to use your flathead screwdriver to hold the bolt in place inside of the tank and screw the bolt on from underneath.


And number 2, be sure not to overtighten the nuts. The washer that is compressed or sandwiched between the bolt head and the inside wall of the toilet tank is what’s keeping the water inside the tank.


Overtightening can crack the porcelain tank or base. Its normal for the tank to be able to move a little front to back. If your toilet does not fit jamb-up tight against the rear wall, you want the tank to have some flexibility so that if someone leans back on the tank while seated that the tank doesn’t crack.


Remember to take your time with this one. If you have the opportunity to start on this early in the day you should. There can be some trial and error when doing plumbing repairs, and it would be a real inconvenience if you discover that you don’t have exactly what you need to finish, and the hardware supply store has closed. Start early, take your time and think things through and give yourself ample time to finish the project.