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  1. #1
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    Can't get my crank bolt off!!

    I'm having serious issues removing my crank bolt. I've watched about every you tube video out there, and all of them remove the bolt with ease using a standard socket wrench. My problem is that none of my sockets fit the bolt! 1/2 is too big, 7/16 is too small. 13mm too big, 12mm too small. The only thing that fits is my 8mm allen wrench which I cant get enough torque on to loosen the bolt. Is there a special tool that I need for this. Any help would be greatly appreciated!! Can't get my crank bolt off!!-photo-2-.jpg

  2. #2
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    An 8mm Allen is the correct tool. Don't use any of the other stuff you mentioned. If you cant break it free with your 8mm, try using some jolting force instead of slowly trying to muscle it. Hit it with the heel of your hand. quickly drop some body weight on it, or hit it with a hammer.

  3. #3
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    or run to Sears (or somewhere similar and get these:


    Sears.com

  4. #4
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    Hex bit worked instantly! Thanks a lot!!

  5. #5
    on the flats
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    I have always kept some hold handle bars around to put on the end of the allen wrench for extra torque. Grease that bolt when you reinstall.
    i only ride for fun.

  6. #6
    Hi.
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    Quote Originally Posted by ridefast84 View Post
    I have always kept some hold handle bars around to put on the end of the allen wrench for extra torque. Grease that bolt when you reinstall.
    Yeah a breaker bar - good call. I have both pieces of an old bar and a beat up seatpost I use as a breaker bar.

    Also, while applying rotational torque, I hit the bend of my hex wrench directly towards the bolt with a hammer. That usually does the trick unless there's some kind of rust going on.

  7. #7
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    the longer the bar, the more torque you will get. I use a 3 ft piece of sched 40 PVC on a ratchet. You dont even need to hit it, apply the torque smoothly to avoid stripping

  8. #8
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    Buy a tube of 'anti-seize' at the autoparts store for the threads when assembling, good stuff!

  9. #9
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    I've had impossibly stuck bolts that my bike shop could not even unstick for me. I actually had luck in getting it free by heating it with a blow torch for a minute. That freed it up like it had never been stuck at all. It was very satisfying. (of course that's gonna be a last resort.)

  10. #10
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    Quote Originally Posted by Stegerman View Post
    or run to Sears (or somewhere similar and get these:


    Sears.com
    Hex bits are underrated.. those expensive blue handled hex wrenches look nice when hanging on the pegboard, but as a DIYer I reach for my socket and hex bits first for anything that requires some torque.

  11. #11
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    Quote Originally Posted by nickp37 View Post
    I'm having serious issues removing my crank bolt. I've watched about every you tube video out there, and all of them remove the bolt with ease using a standard socket wrench. My problem is that none of my sockets fit the bolt! 1/2 is too big, 7/16 is too small. 13mm too big, 12mm too small. The only thing that fits is my 8mm allen wrench which I cant get enough torque on to loosen the bolt. Is there a special tool that I need for this. Any help would be greatly appreciated!!
    It shocks me someone would even consider using any socket on that part....
    Put a mountain biker in a room with 2 bowling balls and we'll break one and lose the other - GelatiCruiser

  12. #12
    human dehumidifier
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    ^ people aren't taught to use tools anymore unless they take up a trade requiring it. It's a shame really.
    I Just Wasn't Made For These Times

  13. #13
    Hi.
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    Quote Originally Posted by wv_bob View Post
    ^ people aren't taught to use tools anymore unless they take up a trade requiring it. It's a shame really.
    Hey man, that's the average bike shop's bread and butter you're talking about.

  14. #14
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    1/2" breaker bar and 8mm allen and i'm more than 100% sure its going to break loose.

    i also work with cars so the 'heavy' stuff becomes handy as well in bikes.

    just don't use those stuff in tightening unless you want to change your bb's.

  15. #15
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    I agree with Spyghost, try using some sort of breaker bar. If that doesn't work, then apply some heat to the bolt, and that should make things much easier.

  16. #16
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    Re: Can't get my crank bolt off!!

    Heat is overkill. I've needed to heat something maybe once every few years. A breaker bar of proper length and good penetrating oil is good for 95% of cases, while shocking the stuck part with a firm tap from a hammer followed by the breaker bar takes care of almost all the rest.

  17. #17
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    It depends on how long the bolt has been in the crank, the weather the owner rides in, perhaps no grease on the bolt, etc... I do agree that there are lots of other alternatives, but as someone who has worked in shops for many years.. sometimes there is no other choice.

  18. #18
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    Quote Originally Posted by wschruba View Post
    Heat is overkill. I've needed to heat something maybe once every few years. A breaker bar of proper length and good penetrating oil is good for 95% of cases, while shocking the stuck part with a firm tap from a hammer followed by the breaker bar takes care of almost all the rest.
    If red locktite is involved heat is about the only choice for something stuck. For rust I like penetrating oil with impact driver or a hammer in the right spots.
    Quote Originally Posted by wv_bob View Post
    ^ people aren't taught to use tools anymore unless they take up a trade requiring it. It's a shame really.
    Whenever I ask for a hex key and just get a stare, I'll say dude use a 8mm Ikea tool on that crank bolt

  19. #19
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    I guess I would point out that heat removable loctite is beyond overkill, but for the sake of argument, yes, you would need a torch or heat gun to facilitate removing it.

  20. #20
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    Vibration helps a lot. Apply steady pressure on the wrench and pedal. Have someone else tap the cranks/wrench/bolt with a solid object. Brass, a hammer, a rock will work. An empty beer can won't. The key word is "tap". To be safe using this method, don't apply too much pressure at first. If it doesn't come loose the first time, keep tapping and increasing the pressure because when it breaks free... It breaks free!
    I just made this quick vid. I'd need a 3' strap wrench to undo this otherwise. The snapping in the video are the pieces bottoming out and locking together. I'm barely applying pressure when it breaks loose.

    Watch "Tapping to loosen locked threads" on YouTube
    Tapping to loosen locked threads: https://youtu.be/wq90AMTdXrM

  21. #21
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    Nothing like a little tribal knowledge.
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