Removing Rusted Tank Bolt | Homeowner Guide 2025

At one point or another, anyone that owns a toilet will need to do some maintenance.

Although most fixes are pretty simple, some may require a little more elbow grease.

One of the most common maintenance problems is that tank bolts get rusty and difficult to remove, so we’ve put together a detailed guide to help you deal with this issue.

Causes of Rusted Bolts

Toilet wear and tear is inevitable and your tank bolts are no exception. The inside of your tank is filled with water and extremely moist. Chlorine is added to our drinking water for health reasons, however, this chemical negatively affects steel and other metals by accelerating rust.

Your bolts are constantly exposed to that water and eventually they will start to develop rust because of it. Toilet and bolt type have a big role to play in this process.

Older toilets will need more maintenance over the years. With proper care, toilet components can last years, but as your toilet ages you’ll need to assess whether it’s more economical to repair a component as it breaks, or to replace the whole toilet.

The type and quality of bolt used is also crucial. Manufacturers produce bolts of all metal types and sizes. To ensure the right fit for your toilet when buying replacement bolts, bring your old bolts along.

The Repair Guide

 Pro Tip:  Before you start any work on your toilet, drain the water from the bowl.

First, turn off the water supply line by rotating the nearby valve. Then, flush the tank and remove any remaining water with a sponge.

If you skip this step, the water may reach the floor, splashing you and your bathroom, when you loosen the bolts. Make sure to put a towel around the toilet too, even if you have a tile floor.

This will help prevent any mess or damage to the area while you get to work.

Checking Tank Bolts

You can find the bolts by simply checking the bottom of your toilet tank. If you look closely, you may notice that there are rubber washers that keep the water and moisture inside.

Those washers can get damaged and worn out over time, so be sure to check their condition as well before proceeding.

Good quality bolts are integral to your toilet’s functioning. If they aren’t properly maintained, like in the video below, eventually they will rust and become extremely stubborn to remove.

Removing Tank Bolts Not Rusted

When preparing to remove rusted toilet tank bolts, consider how to remove them if they were in good condition first.

For bolts without rust, you don’t need any special tools, only a screwdriver and a wrench.

To remove, hold the bolt in place with the screwdriver and loosen it with the wrench. Make sure not to tighten it with a screwdriver as this may cause problems later.

Removing Rusted Tank Bolts

As you can see, removing rustless tank bolts is a straightforward process.

However, it’s a bit different when the bolts are rusted, and might take you some more time, especially if it’s a severe case and the tops of the bolts are swollen.

Before going any further, it’s important to assess just how rusted your bolts are. We recommend first going in with a pair of vice-grip pliers and a wrench, like in the video below.

Sometimes you’ll manage to loosen the rust around the bolt this way. Most of the time, however, you’ll need a more serious tool like a hacksaw to cut through the bolt.

Method 1 – Use Penetrating Oils

Penetrating oils are an effective way to clear excess rust during bolt removal. These oils soften and break the rust down, making the bolts easier for you to loosen. Using these oils is a simple, three-step process:

There are a handful of really good penetrating oils on the market. Most of them can be bought at your nearest hardware store for a good price. Liquid Wrench, Kano, and WD-40 won’t let you down. Our recommendation, however, is B’laster. This brand of penetrating oil is most effective, and the oil leaves a protective lubricant behind after removal.

 Pro Tip:  Penetrating oils are not only great for bolt removal. These oils help protect your bolts and prevent future rust!

If you try to remove rusted bolts using a screwdriver, the tops might turn into dust. If this happens, there are a few things you can try:

Method 2 – Use a Mini Hacksaw

A mini hacksaw is a very handy tool that can help you remove rusted tank bolts. Since its blade is flexible, you might be able to push it under the head of the bolt – although you may need to cut the rubber elements to reach the bolt head.

When you have the saw in place, you should be able to cut through the bolt easily.

Method 3 – Reciprocating Saw

Using this device would make the process much faster than with a hacksaw, but they’re a bit more difficult to find. Using this tool can also be riskier since you may easily damage the toilet.

When using the reciprocating saw, you’ll see a metal blade on the saw, which can come in various sizes. For example, there are short, 6-inch blades that will give you more control while working or longer blades that allow you to do the job from distance, which some people might find easier.

Using the right-sized blade, you should be able to cut through the bolt and remove it, although be careful to avoid hitting the tank with the blade or you may damage your tank.

Method 4 – Bolt Cutters

If nothing else works, you should try using bolt cutters. Although more expensive, bolt cutters are an ideal tool to use if the bolts are already loose but won’t come off, and will definitely do the job in this scenario.

Installing New Bolts

Now that you have removed the old, rusty bolts, it’s time to install new ones in place.

First, make sure to screw the nut onto the bolt, and not vice versa. Also, don’t over-tighten anything, which can damage the weak material or otherwise be difficult to remove when it gets rusty.

You want the toilet to be fixed, but don’t worry if it’s slightly flexible – it’s still better than damaging the tank.

Beware of Over-Tightening

In most cases, toilets are made from vitreous china which is not as durable compared to other materials like stainless steel. If you over-tighten the bolts, the material will crack and cause leaking. The leaking can be just a couple of drops at first, but it has the potential to become a much bigger problem. But how can you be sure when to stop tightening?

We can advise you to start by hand or with a small wrench and tighten both bolts simultaneously. When things start to get firm, you should be very careful. Most likely, you’ll only need to turn them for about half a turn more at this stage.

Types of Replacement Toilet Tank Bolts

When you’re shopping for new bolts, try to avoid zinc-plated steel and go instead for bronze bolts. Bronze is hardier than steel and doesn’t rust as quickly and makes for far better wear and tear. You want to find not only brass bolts, but also brass washers and nuts.

For older toilets, we recommend Kohler Tank to Bowl Bolts – these can be found in most big hardware stores. If your toilet is an old-style Eljer toilet, we recommend the Lasco Eljer Bolt Kit.

Our Opinion

If you’re struggling to remove rusted toilet tank bolts, we hope this guide will help you out. This is a risky process since you can easily damage the porcelain, but if you follow our DIY instruction guide properly, you’ll have those bolts removed in no time!