I've ruined two hex wrenches trying to remove my pedal. I actually got one off after blasting it with a hot-air heat gun for a while. The other one remains stuck and Yes, I'm turning it the right way.

I tried penetrating oil as well as the heat gun. (Side Question: Can my heat gun hurt the steel crank arm?)

What is my next step? I've got an extra crank arm somewhere so maybe I cut my losses and go with that new crank arm.

Lesson for all of you: use anti-seize compound when assembling!

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    I've never encountered a pedal that could not be removed, if unscrewed in the proper direction, and if it wasn't rounded over from prior attempts. But I'd probably remove the pedal from it's shaft and then use Vice Grips or some such to unscrew the shaft. – Daniel R Hicks Jun 28 '18 at 22:04
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    Not wishing to be obvious, but it doesn't have 15mm flats on the pedal side also? The ones I've seen do. – Henry Crun Jun 29 '18 at 8:01
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    @altomnr No. It is steel. – mcgyver5 Jun 29 '18 at 17:24
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    When using an Allen wrench in this situation you'd certainly have to use a single L-shaped wrench, not one bit of a combo tool. And use a 2-3 foot pipe on the longer side (with the shorter side in the socket) so that you can get enough leverage. Helps to have a second person who will hold some sort of rod or screwdriver running through the crank to keep it from turning. – Daniel R Hicks Jun 29 '18 at 22:30
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    A long-armed 3/8'' square-drive handle with a 6 (or 8mm) hex attachment and no pedal will resist. – Carel Jun 30 '18 at 14:06

Stuck 6mm-only pedals can be a very tough situation, unfortunately.

Presuming an aluminum crank, heat, either from a heat gun or torch, is a method some mechanics go to quickly here. The idea is the different materials expanding and contracting at different rates thermally shocks the corrosion free. Personally I'm squeamish about this and never do it on other people's bikes, out of fear of metallurgical consequences (ruining the heat treatment etc) that might not be obvious. That said, it's a pretty common practice and probably unlikely to bite you in any meaningful way.

I tend to soak it in some kind of penetrating oil for at least a day. Lately I've been using Finish Line Chill Zone, which thermally shocks it using cold. I put a plastic bag around the pedal, rubber band it around the crank, and position it so the threaded part is being bathed in oil. This also contains the mess and smell, which is nice.

To do the actual breaking free, what I do if possible is clamp a 6 poking straight up in the vise, put the crank on top of that, and try to find some way of applying massive leverage to the crank, usually via a Park FFS. I've also clamped the cranks using smooth jaws and rags, but this is pretty likely to do some kind of marring to the cranks anyway given all the force involved.

  • So you would remove the crank from the bike to do this? I've found it easier to leave it on the bike and use my body weight on the saddle,one foot on the other pedal, and other foot on the tool. Pedals with flats I'd have that pedal forward, and push the pedal spanner down with my heel. For a hex-only one I would put the target pedal backward, with a P-shaped hextool in the hole, so the heel of the tool rests on the chainstay, or perhaps on a ~5" length of wood propped off the ground. – Criggie Jun 30 '18 at 9:52
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    For this specific situation, hex-only,, I do take it off. I find it makes managing an enormous cheater bar easier. – Nathan Knutson Jun 30 '18 at 23:25

The heat could potentially alter the tempering of the alloy, but I'm not sure it's going to be catastrophic. As for the pedal, have you tried extending your leverage with a breaker bar of some kind? Aside heat and penetrating oil, there isn't much more that can be done.

General use grease on the pedal threads should always be used. Always.

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    Fifty to one hundred degrees C won't do anything to bad to metals, but its enough to help easing oil / penetrating oils to get into a closely tightened thread. Just be careful to avoid igniting any petroleum products, and to keep heat away from carbon, plastics, and rubber. – Criggie Jun 29 '18 at 1:52
  • Yeah, I read the OP again and saw he mentioned heat gun. I had a propane torch in mind when I answered. – Gabriel C. Jun 29 '18 at 12:46
  • It is a heat gun (like a high powered hair dryer) with no flames (yet). I did use a breaker bar. Problem is that 6mm width can't take the leverage. That is how I ruined one of the hex wrenches. The other hex wrench I ruined was a Park Tool HT-6 which comes long enough to apply enough leverage to ruin it without a breaker bar! – mcgyver5 Jun 29 '18 at 15:22
  • Aside from letting oil seep in for a few days, I have no idea. I had trouble with one of my pedals once and removed the crank from the BB axle, letting the threads sit vertically for a day with like a mL of Tri-flow on top of it. Came off super easy afterwards. Vise-grip on the axle with a sufficiently long lever is the next option on my list. If that doesn't work, drill the pedal axle out (that sucks). – Gabriel C. Jun 29 '18 at 15:38
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    @mcgyver5 6mm is quite small for a pedal. I've normally seen 8mm and rarely 10mm hex sockets on pedals. Do your pedals have flats on the outside? Could be a pedal spanner will work better, if there are flats to work with. – Criggie Jun 29 '18 at 21:06

Pedals are extremely tough to get off in my experience. A normal hex wrench won't give you enough leverage, you need a special pedal wrench such as those found by this search:


They seize up, but are often tightened with a high torque. The right tool will help you get it off. I too have ruined several hex wrenches until I got a proper pedal one.

Also remember, the left pedal spindle is reverse threaded, so turn clockwise to remove the pedal when facing the crank arm. The right side is normal, so turn it anti-clockwise to loosen it.

  • So tough in fact, that once I bought a whole new crankset! Possibly a bit overkill where an impact driver and some WD-40 may have fixed the problem.. – John Hunt Jul 5 '18 at 8:32

I've not tried this, but another solution might be to use an impact driver and a medium hammer.

A manual impact driver takes impact forces and translates them into rotational forces, plus the impact helps keep the tool's bit deeply in the hole.

Thanks Wikipedia! From https://en.wikipedia.org/wiki/Impact_driver

Just be sure its set to "undo" not "tighten" ! Any hammer will do - you don't need a Park branded one, but they have the HMR-4 and HMR-8

This tool is not to be confused with a rattle gun or impact wrench. They tend to look like cordless drills, and I have no experience with them. Probably overpowered for a bike.

  • Last thought - if the pedal's 6mm hex slot is completely stripped out, then you're never going to use this pedal again. So disassemble it and use a pair of plumber's stillsons on the shaft, and then biff it in the bin. – Criggie Jun 30 '18 at 10:05
  • Criggie. I laughed out loud at "Just be sure it is set to "undo" and not "tighten". Totally something I would do. Thanks for the information. – mcgyver5 Jun 30 '18 at 19:58
  • @mcgyver5 there is personal experience behind that comment - fortunately it was a landrover brake drum and survived. – Criggie Jun 30 '18 at 22:47
  • What a cool tool, must get one! – John Hunt Jul 3 '18 at 10:43

I used an 18V impact driver with over 200Nm torque on mine after a good soaking in WD 40 and they still won't budge. My bike is only 18 months old!

The impact driver and 6mm hex did not shift it and my open-ended 15mm spanner started to round off the flats.

I solved the problem by dismantling the pedals off the shafts and got a ring spanner on the pedal nut and blocked the crank against the frame with a block of wood. Then my putting my heel on the spanner and applying all my weight in a downward force I managed to crack them off. I was replacing the pedals anyway but beware if you dismantle the pedals the bearings will probably fall out.

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    "good soaking" and "WD40" is a contradiction. WD40 isn't a penetrating oil. Get some PB Blaster or Kroil. – Andrew Henle Jul 8 '19 at 14:39
  • OP's pedals don't have flats, but your idea of removing the pedal body could work for some situations. A pair of stilsons (a pipe wrench or monkey wrench) will be needed to grab the round shaft and remove it. Or delicate use of a grinder may be needed to make a flat or somewhere to grip the shaft for untwisting. In your case, is it possible you mixed up left and right hand threads at some point? I know I still do sometimes. – Criggie Jul 9 '19 at 0:30

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