How to Remove Rusted Exhaust Flange Bolts?

Exhaust flanges are a piece of metal that attaches to the engine on your vehicle and has enough room for custom pipes. They require an exhaust gasket between the header flange and engine head for a water-tight seal. Flanges are sealed with bolts, sometimes because of corrosion, they become rusted. this post is about how to remove rusted exhaust flange bolts.


What are Flanges?

Flanges are designed to fit your engine’s port shape, bolt spacing, and port size, making it easy for exhaust gas to flow through. It’s easier to explain with the diagram and picture below.

how to remove rusted exhaust flange bolts

They are an essential component of the system for your car. Without them, the system may not function correctly, resulting in airflow problems or road vibration, resulting in your vehicle running poorly and being a danger to the people inside for the leak in your exhaust system. This can become especially dangerous if you have any leaks near the passenger compartment. The gases released are incredibly toxic, so it’s essential to take care of any leak as soon as you can.

It will be troublesome if the part is rusted and becoming stubborn to remove while you need it off as the first required step. Not to mention because there’s so much heat on an exhaust manifold, these bolts are tough to get off. With this in mind, you may want to fix this or install a new exhaust system altogether.

What are the Options to Remove the Bolts?

Removing a rusty bolt is challenging but not impossible. With a bit of patience, any at-home mechanic can tackle the challenge. Resist the temptation of using excessive force. This could cause you to break a blind stud, which could mean hours of drilling out the busted shank. As with all projects, assess the situation and plan carefully. Let’s consider all of the options first on how to remove rusted exhaust flange bolts.

Penetrating oil

Penetrating oil like PB Blaster is one of the most valuable things you can have in your toolbox. You can use it as a first measure to loosen stuck rusted exhaust flange bolts and act as prevention. They’re less likely to rust and become useless.

Big breaker bar



how to remove rusted exhaust flange bolts

A breaker bar or long-handled ratchet will give more leverage. Use a steady, even pressure, paying close attention to the feel or each turn. Don’t forget to wear padded mechanics gloves to reduce skinned knuckles.

Impact wrench

If you need all the power you can get, use impact wrenches. They are the first tool of choice for many techs working on an exhaust system to break loose frozen nuts. Pneumatic wrenches make the most power, but for the lower price, go for cordless impact wrenches to remove the rusted exhaust flange bolts.

Ball joint splitter

how to remove rusted exhaust flange bolts

Get a long-reach and sturdy Ball Joint Splitter. Tighten the bolt on the splitter, and put some metal between the actuating arm and the tip of the protruding stud. This leaves a perfect hole ready for a new (this time stainless steel) bolt.

Hacksaw, or air hammer with a chisel bit

The idea is to chisel out the bolt, and once it’s deformed, it will be easier to remove.



Grind the upper part of the bolt so you can remove it with a flat-head screwdriver.

how to remove rusted exhaust flange bolts

Nut splitter

Use the tool to cut the bolt head entirety. With the nut splitter, you can expect clean results without damaging the exhaust flange.



You can heat the bolt red hot and then hammer on as tight a socket as you can find. If you can’t find a torch, a muffler shop should be able to torch the broken stud out, and then you can install a nut and bolt through the hole.
When you’re done, you can drill into the face of the nut. Even if the nut is high-grade steel, it can be drilled with a sharp conventional (high-quality HHS) drill bit. Start with a tiny size drill bit, like 1/8 inch or so.


How to prevent exhaust flange bolts from rusting?

You can use copper anti-seize on the market that holds up well on exhaust nuts and bolts.

How much does it cost to install an exhaust system?

Getting a, for example, cat-back exhaust system installed is a simple procedure. There are places in your local area that do the installation for only $100, plus you can occasionally get it done for just $20 if you happen to be nearby the muffler shops that offer this service.

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