How to remove a stripped bolt

18th May 2015

There’s nothing more more annoying than a rounded, or stripped, bolt. Common locations include seat posts, and cleats – common reactions include frustration and anger.

You know you’ve rounded, or stripped, a bolt when you insert an allen key, and rather than slotting in nicely, and turning, you’ll find the tool simply swivels in the bolt.  Pieces of metal have been stripped away, so the key no longer fits the lock, so to speak. You might also notice tiny files of metal in the area.

If you’ve already rounded off a bolt – and are sitting next to your bike sweating for fear that you’re going to have to ride with your set too high/low for ever more, or buy some new cycling shoes because you can’t remove the cleats – don’t: there are ways to remove them.

We spoke to Jenni Gwiazdowski, Director at the London Bike Kitchen, to find out how she would go about removing a rounded bolt, and she gave us a couple of options:

  • You can fill in the hole with super glue and stick something t-shaped into it, let it dry, and then use the handle to turn it out
  • Try cutting a slit into the bolt, and then sticking a flathead screwdriver into it – only do this if you feel confident, if not – ask a mechanic – regardless, the good news is that is very effective when done correctly:
  1. To do this you will need a Dremel Rotary Tool or a Hacksaw – just cut yourself a narrow slot, right across the middle of the bolt – effectively overriding the rounded hole in the centre…
  2. Then you’ll be able to simply slot a screwdriver into your new groove – snazzy!

  • Jenni also added that  “sometimes you can just cut the bolt in half with a dremel, hacksaw or anglegrinder, or you can drill a hole into the bolt and drill it out in reverse” – we found a video demonstration of the latter but this is probably not best done by a mechanic who knows exactly what they’re doing.
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Jenni did add: “this is a touchy, dangerous subject”. All these methods are very common and effective, but if you’re at all unsure, take your bike, or shoe, to see a mechanic – they will no doubt be able to help you, and failed attempts could make the problem worse.

How Not to Round Off Bolts in the First Place

We’ve put this second because no one in the situation above wants to be told how not to get there – but once you’ve sorted out your stuck bolt, there are a few ways you can prevent the problem happening again:

  • Jenni’s top top was simple – be more careful when loosening or tightening bolts: “Make sure you use the correct sized tool for the bolt, and make sure it’s fitted in all the way into the bolt. Too often people only put in the tool halfway and then proceed to turn; there just isn’t enough traction here to make sure that the tool is fitting properly and it will slip, eventually rounding the bolt. Apply pressure both into the bolt, as well as in the turning direction, to ensure any slipping is minimised.”
  • Multi-tools are great on the go – but use a proper allen/hex keys when you’re at home, the longer handle gives you better leverage
  • Never overtighten bolts – seat posts, headsets and cleats usually have written on them (or with their accompanying instructions or owners handbook) a recommended torque – this is written in ‘newton metres’ – such as 5Nm or 10Nm. In an ideal world, you’d use a torque wrench to ensure you get the right tightness, but if you don’t have one, ask someone to show you how tight it should be, and after some practice you’ll learn the ‘feel’ or 5 or 10Nm.
  • Cleat bolts can be a real pain – the metal is often very soft, so they round very easily. Keep them clean, don’t walk too much off the bike (or use the cleat covers that no one ever uses…) and avoid muddy, gritty surfaces – this helps to keep them in better condition, which makes removal easier.
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Greek History Time!

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.

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 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.

Hot Shackle Bolt

Heating a bolt is an effective way to get it un-stuck, but be careful! (Image/Jeep Cherokee Forum)

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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.

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.

Broken Bolt

A broken bolt isn’t the end of the world. There are stud extractors and other specialized tools that can help. (Image/Rennlist)

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