How to Remove Rusted Toilet Tank Bolts in 7 Steps

Last update:

How long has it been since you’ve last opened the toilet tank to fix something inside?

I’m sure it’s been a while because your tank bolts are rusty, and you’re wondering how to replace them. There are two possible outcomes — you’ll either unscrew the bolts or cut them with a hacksaw.

But the task is a bit more complicated than that, so you’ll need a few more tips to do the job properly. This article will show you seven steps on how to remove rusted toilet tank bolts.

A Step-By-Step Guide on How to Replace Rusted Bolts

Tank bolts maintain a sealed connection between the toilet tank, the fill valve, and the pipe leading to the toilet bowl. On most toilets, there are two bolts on either side of the tank’s bottom.

When bolts are rusty, you can remove them by following seven easy steps.

Step 1: Close the Water Supply Line

The first step is closing the shut-off valve and preventing water from entering the tank. Turn the handle clockwise to shut the water supply line.

If you cannot do it barehandedly, use a pair of pliers.

Step 2: Flush the Toilet to Remove Water From the Tank

You need rusted bolts to be dry and accessible, so make sure to flush the toilet before anything else. Now you can remove the tank lid and see the bolts on the bottom of the toilet tank.

Step 3: Clean the Remaining Water With Towels or Sponges

After flushing the toilet tank, there might still be some water left in it. If so, wipe it with a towel or sponge. Cleaning the tank’s bottom should be easy because it’s plastic, so you can pick leftovers in seconds. 

That also allows you to approach rusted bolts easily. 

Step 4: Use a Penetrating Oil to Loosen the Bolts and Nuts

When rust builds up on bolts and nuts, it makes metal elements difficult to unscrew. You can use a penetrating oil like CRC Screwloose to remove the sturdiest pieces of rust.

Spray the oil on rusted toilet tank bolts and nuts. After that, wait for 10 minutes because the oil needs time to penetrate rust. The oil has a high concentration of lubricants which break down metal surfaces and help to reduce friction during movement.

In most cases, one application is enough for the bolts to turn properly.

Step 5: Unscrew the Bolts

Once the bolts loosen, you can unscrew them with a flathead screwdriver and a pair of pliers. Hold the pliers firmly to secure the nut and unscrew the bolt with the flathead screwdriver. Place a screwdriver directly on the bolt head. 

Turn the bolt counterclockwise to remove it. With penetrating oil, unscrewing the bolts should be effortless.

Step 6: Cut the Bolts if You Cannot Unscrew Them

Sometimes it’s impossible to unscrew bolts, no matter how much penetrating oil you spray. In this case, you’ll have to cut the bolts using one of these tools:

Toilet bolts are hanging from the bottom of the tank facing downward. Your job is to place the cutting tool horizontally between the nut and the tank. Now you must push the saw back and forth to cut and remove rusted bolts.

You will instantly notice the rusted bolt cracking, but it might take you a minute or two to cut it entirely. Be very careful when cutting bolts because you are operating a dangerous tool.

Step 7: Set New Bolts

After removing a rusted tank bolt, you need to install a new one. New toilet tank bolts are in the package, along with nuts that secure bolts into place.

First of all, clean the holes left after cutting to make room for new sets of bolts and nuts. You can insert the bolt in the threaded nut with your fingers.

After that, place the pair on the tank and line up the holes with it. Use a flat screwdriver to install the new set firmly. While doing so, you can hold the nut with a set of adjustable wrenches or pliers.

Remember not to screw the bolts too tightly because toilet tanks are plastic. If you tighten bolts too much, you risk cracking the tank.

Why Do Tank Bolts Rust and How to Prevent It

Tank bolts are constantly under the water or in contact with moisture, so it’s not surprising that they occasionally develop rust. 

Condensation also impacts bolts. It creates a layer of chemical residue on metal surfaces, which can lead to corrosion.

To prevent tank bolts from rusting, you need to get the right hardware. Many bolts and nuts aren’t corrosion-resistant. 

The best choice is brass, a material that fends off rust and resists corrosion. Fluidmaster brass bolts also work well with humid air and water, so there won’t be any corrosive residue.

Reasons to Remove Rusted Bolts

When you notice rusted tank bolts, you need to remove them as soon as possible. Ignoring rust for an extended time can cause problems with your toilet tank.

Toilet tank bolts are critical to the integrity of your toilet tank. They keep the tank together, but rusty stains will damage bolts and cause cracks. Water from the tank may start leaking soon.

Rusted bolts also corrode inside the toilet tank, creating further damage on the inside.

The Bottom Line

Rusty toilet tank bolts can be annoying, but replacing them with a new set is easy. Here’s what you need to do:

  • Step 1: Close the water supply
  • Step 2: Flush the toilet to remove water from the tank
  • Step 3: Wipe off remaining water droplets from the tank
  • Step 4: Spray the rusted toilet tank bolts with penetrating oil
  • Step 5: Unscrew the bolts with a flathead screwdriver
  • Step 6: Cut the bolts
  • Step 7: Set the new set of bolts and nuts

Perhaps it sounds complicated, but it’s only a 15-minute task. Do your best to follow our steps, and you will remove rusted toilet bolts like a pro. 


How to cut toilet tank bolts?

You can use a mini hacksaw to cut toilet tank bolts. Be careful while operating a saw because you could damage the surrounding area and hurt your hand or fingers.

How to keep toilet tank bolts from rusting?

You should buy corrosion-resistant toilet tank hardware. This type of bolt is much more durable and will fight off rust for a long time.

How to clean rusted toilet tank bolts?

You can use steel wool, sandpaper, or vinegar. Penetrating oil represents a more advanced alternative. Keep in mind not to use water because the moisture will get the bolts wet again.

Leave a Comment