(Image/Steve Baur)

A rusted, seized bolt or nut can turn an easy project into a nightmare.

In fact, mechanics have been known to hold a lucky rabbit’s foot or refuse to work on Friday the 13th for that very reason.

But removing a stuck bolt doesn’t rely on luck—it relies on the proper preparation and tools.

OnAllCylinders contributor Jim Smart wrote an in-depth article that covers a lot of the stuff we mention here, but goes deeper into the topic of thread repair. You can check it out here: Taking The Sting Out of Damaged Threads

Plan Ahead.

If you have the luxury of planning a bolt removal in advance, then take advantage of your head start by spraying the bolt with penetrating oil.

A quality penetrating oil does two things:

It will act as a mild solvent to eat away at rust, plus it will lubricate the threads, which will make for an easier extraction (and mitigate the risk of snapping a bolt due to corroded threads.)

Some folks will make their own blend of penetrants using common garage substances like automatic transmission fluid, acetone, and candle wax—but we’re inclined to trust the off-the-shelf stuff.

Start several days in advance, spraying the bolt or nut every day with a fresh blast of penetrant.

Don’t be stingy—really soak the nut or bolt down. Allow the penetrating oil a good chance to creep in to the bolt threads.

If the bolt or nut is located in a tight space, try to remove as many obstacles (brackets, panels, etc.) as you can to ensure your socket and wrench/breaker bar has enough room to seat and turn properly on the fastener’s head.

Use the Right Tools.

When it comes time to remove the bolt, take your 12-point socket and hide it in your sock drawer next to your four-leaf clover—you won’t need either one.

Use a 6-point socket for a traditional hex-head bolt. That will reduce the chance of accidentally rounding the head or nut.

If your bolt in question is an Allen or Torx, make absolutely-positively sure you’ve got the right-size bit. (AMC and Jeep folks know what we’re talking about.)

Take a wire brush and knock-off any corrosion on the bolt head. You want to ensure your socket is seated fully onto the fastener.

Don’t lead off with an impact wrench or breaker bar. Instead, try to see if you can break the bolt free with your trusty socket wrench. You don’t want to risk shearing the bolt head off with unnecessary force.

Greek History Time!

Using something like a breaker bar or wrench extender can give you a powerful mechanical advantage. (Image/Mueller Kueps)

If, after all that, your bolt is stuck—call Archimedes.

Archimedes was an ancient Greek gearhead who was the first to mathematically explain the mechanical advantage of a long lever. In other words, he helped invent the breaker bar. Applying gentle force, use the bar’s leverage to apply more turning strength to the bolt head. Feel is important, and if you think you’re going to round or shear the bolt head, back off the fastener.

If a breaker bar still won’t release the bolt, it’s time to contact Prometheus.

Heat is often a go-to tactic for extracting a seized bolt. (Image/Jim Smart)

In Greek mythology, Prometheus stole fire from the gods and gave it to the mortals. Now, thanks to him, you can use that fire to un-stuck your bolt.

Using a torch, heat the bolt head or nut. Due to thermal dynamics, the bolt or nut will expand. The hope is that expansion and contraction process will also un-seize the bolt, breaking the corrosion that grips the threads.

Obviously, you’ll want to take great care to avoid any damage caused by the intense heat. Clear away any solvents, and make sure you’re not using your torch near a fuel line and oil-weeping gasket. Your torch will also quickly melt plastic and rubber, so be mindful of bushings, mounts, and boots. (Mini torches and induction tools are really handy for this sort of job.)

Keep the heat centered precisely on the bolt head or nut for about 20-30 seconds, and then let it cool.

Though opinions differ, we recommend waiting for the fastener to cool back down before you attempt to turn it. Again, the magic of this method occurs in the expansion action breaking loose the corrosion.

While heating a bolt is an effective way to get it un-stuck, be careful to contain the heatsoak out of other areas! (Image/Summit Racing)

Impact Play.

An electric or air-powered impact wrench is the stuck bolt’s arch nemesis. If you’re lucky enough to have one, remember to try to loosen the bolt by hand first—too much torque too fast can spell disaster to a rusted fastener.

In addition to the rotation strength of the wrench, the impact action will help shock the bolt free, loosening corrosion that may be gripping the bolt.

Preventative Maintenance.

There are several things you can do to help prevent the bolt getting stuck in the first place.

  • Proper Torque. Avoid over-tightening bolts.
  • Thread Lubricant/Anti-Seize. Apply a quality thread lubricant to the bolt or stud to prevent seizing caused by galvanic corrosion.
  • Paint the Fastener Heads. A simple coat of spray paint will keep rust and corrosion off the fastener head, and prevent moisture from creeping into the threads.
  • Brush Up. Don’t be shy about occasionally using a wire brush on the fastener head. It will keep muck and moisture out of the threads.
  • Add a Coat of Grease or Oil. If you’re unable to paint the heads, then periodically spraying them down with a penetrating oil or applying a small dollop of grease will work just as well. It’s also smart to do the same thing to the bolt’s threads, if they’re exposed behind a bracket.
Once the hardware is out, a bath in something like Evapo-Rust will help prepare them for reinstallation—if they’re not too-far-gone, that is. (Image/OnAllCylinders)

A Lucky Turn?

Hopefully, following these tips has been helpful, and your bolt or nut is lying harmlessly on the cement in front of you.

If it isn’t, and you’ve rounded your fastener head or sheared it off completely, don’t despair.

There are products out there to remedy a rounded nut and extract a broken stud—and none of them involve knocking on wood, wishing on rainbows, or crossing your fingers.

A broken bolt isn’t the end of the world. There are stud extractors and other specialized tools, like this one from OEM Tools, that can help. (Image/Summit Racing)
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Author: Paul Sakalas

Paul is the editor of OnAllCylinders. When he's not writing, you'll probably find him fixing oil leaks in a Jeep CJ-5 or roof leaks in an old Corvette ragtop. Thanks to a penchant for vintage Honda motorcycles, he spends the rest of his time fiddling with carburetors and cleaning chain lube off his left pant leg.