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  1. #1
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    Stripped crank bolt and worried about BB threads

    Well, I had good intentions yesterday... was going to take the crankset & BB off to fix a few creaks down there. Crankset is and 'older' Truvativ Stylo Team ISIS. BB is a Gigapipe SL, I recall; bike is a ~2007 Chumba XCL.

    Got the non-drive side crank off no problem. Started on the drive side and was too lazy to think about which direction to loosen the bolt. Turned it one way & it got harder so I went the other way. Next thing I know the bolt is turning easily and the crank isn't coming off. Not only that but the crank remained tightly mounted (no play). So I moved to the BB ring on the non-drive side to at least take something apart. Started loosening the ring and it took a bunch of torque to loosen. I started worrying that I was cutting new threads because the threads that were showing were mighty clean, but it may be that the brick-red anti-seize that Truvativ used was simply scrapped off. I realize that if I had installed the ring cross-threaded, there's only one thing to do and that's remove it and cross my fingers that the frame is okay. After those two mishaps, I just decided to stop, think, and write this thread.

    So i guess I only asking how I can get the drive-side crank off if the bolt is stripped and of course I'd appreciate any suggestions or comments about the BB issue.

    cheers..... Hobart

  2. #2
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    what bolt is stripped? the one that tightens down the crankarm into the bb, or that self extractor nut thing that threads into the crankarm and when you loosen the regular bolt it is supposed to bump into the inside of the self extractor thing to pop off the crankarm.

    read the directions.

  3. #3
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    Most ISIS & Octalink cranks I've seen have a self-extracting crank bolt. Does yours have an 8mm fixing bolt and 10mm extraction bolt? If so, which did you torque and is now spinning freely?

  4. #4
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    The BB axle and bolt are hardened steal, so I'm guessing he stripped either the extraction threads in the crank, or the extractor bolt threads. This is a good reason to always use a proper crank extractor tool rather relying on those thin aluminum extractor bolts.

  5. #5
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    The crank bolts are not the typical self-extracting type but when you loosen the bolt the crank arm will come off since it's a simple bolt attached to the crank arm. It's a 'stepped' allen head with both 8mm and 10mm (guessing at the exact size since I'm not at the bike). The 8mm was stripped while the 10mm rotated with (or bound to) the crank. The BB shell was removed with a Park BBT-18 tool. The 8mm is normally how I remove the crank arms so it's part of the 12mm (or 15mm, not sure) 'bolt' that threads into the ISIS BB.

    I tried to rotate the 10mm allen head but it wouldn't budge. However there's not much depth to grab onto with an allen wrench.

  6. #6
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    It sounds to me like the self-extracting type in that you would turn the 8mm counter-clockwise and it would then push the crank off the spindle as it backs out pressing against the 10mm extraction bolt which shouldn't move. My guess is you torqued the 8mm clockwise and stripped it, if it's just turning free. You could try to see if you can turn it counter-clockwise and grab a thread. If you can get it going it could still pull the crank.

    If it's not the self-extracting type then the 8mm bolt should come all the way out so you can then thread in the crank extractor tool. When you've pulled the crank in the past did that bolt come out completely, so you could thread in the park (or similar) extractor, similar to what you'd use with a square taper BB? I guess either way if you can't get that 8mm bolt to grab a thread and back it out of there it'll have to be removed some other way. If it's not grabbing onto the spindle at all, you may be able to tap that DS crank off carefully with a mallet.

  7. #7
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    I doubt you stripped the threads on the spindle that the 8mm bolt grabs onto. That is hardened steel. I also doubt you stripped the threads on the 8mm bolt because that is hardened steel also.

    But you say the 8mm bolt turns freely, meaning that it is still trapped inside the crank arm, with the head hitting the 10mm nut? Fine, get a piece of metal, like a bolt, and drop it thru the spindle. unscrew the 8mm bolt on the drive side as much as possible. Hit the new bolt head with a hammer. This will push on your stripped 8mm bolt on the other side, which will push on the 10mm nut attached to the drive side crankarm.
    If this doesn't work, cut off the head on this bolt and make it shorter than the spindle. Then use the 8mm bolt on the other side to push on this new rod.

  8. #8
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    I think these are the same crank bolts that I have - New Truvativ Self-extract crank bolts, ISIS/HWZ - M15/22 (alum) pr | eBay

    I'll have another look tonight.

  9. #9
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    Here's a follow up to my ordeal. So I gave up trying to get the drive-side 22mm crank cap off and took it to the LBS. They eventually got it off (they just drilled and cut it out) but completely ruined the 22mm threads, leaving me no way to use the 12mm self-extracting bolts to remove the crank arm. And when they were done, we found a VERY stripped self-extracting alloy crank bolt. So after MUCH trial and error, I rigged up a gear puller and got the drive-side crank arm off.

    With the crank arms off, it was time to remove the non-drive-side BB cap. It wouldnít budge using the normal ISIS socket. When I tried to use too much torque, the socket started to slip which eventually chewed up the indentations that the ISIS socket fits into. So I got out my big channel locks and it started to back out. Problem was, it became harder and harder as it was unscrewed. Also I noticed that the now visible BB cap threads looked mighty shiny, as if new threads were being cut. Thatís where it sits now. Itís hard for me to believe that I cross-threaded the cup when I installed it some 5 years ago; I recall that it threaded in easily. But I guess itís possible. My plan is to spray it with some PB Blaster or acetone/tranny fluid mix and let it sit for a day, then try again. I hate to think about the prospect of a ruined front triangle.

    So, Iím just looking for comments, recommendations, and worse-caseÖ. Sympathy.

  10. #10
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    Quote Originally Posted by Hobart View Post
    Here's a follow up to my ordeal. So I gave up trying to get the drive-side 22mm crank cap off and took it to the LBS. They eventually got it off (they just drilled and cut it out) but completely ruined the 22mm threads, leaving me no way to use the 12mm self-extracting bolts to remove the crank arm. And when they were done, we found a VERY stripped self-extracting alloy crank bolt. So after MUCH trial and error, I rigged up a gear puller and got the drive-side crank arm off.

    With the crank arms off, it was time to remove the non-drive-side BB cap. It wouldnít budge using the normal ISIS socket. When I tried to use too much torque, the socket started to slip which eventually chewed up the indentations that the ISIS socket fits into. So I got out my big channel locks and it started to back out. Problem was, it became harder and harder as it was unscrewed. Also I noticed that the now visible BB cap threads looked mighty shiny, as if new threads were being cut. Thatís where it sits now. Itís hard for me to believe that I cross-threaded the cup when I installed it some 5 years ago; I recall that it threaded in easily. But I guess itís possible. My plan is to spray it with some PB Blaster or acetone/tranny fluid mix and let it sit for a day, then try again. I hate to think about the prospect of a ruined front triangle.

    So, Iím just looking for comments, recommendations, and worse-caseÖ. Sympathy.
    You could spray a penetrating oil and "walk" the BB cap out. Then take it back to the LBS and have them chase and Face the frame's BB threads.

  11. #11
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    ^ Well, I'd be getting them to do the new BB and crank install too.
    Rimmer - "There's an old human saying - if you talk garbage, expect pain"

  12. #12
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    Photos of crank removal

    I thought I'd show the Rube Goldberg contraption that I used to pull the crank. A three-arm puller doesn't work well with a 4 arm crank, BTW.
    Attached Thumbnails Attached Thumbnails Stripped crank bolt and worried about BB threads-chumba-crank-removal.jpg  


  13. #13
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    The saga has ended; I removed the stubborn BB cap with little incident. There was some thread stripping involved but only on the cap. The BB frame threads seemed okay. A new external BB and Truvativ Stylo crank are now installed using PLENTY of waterproof grease and eased in, then torqued. Although I've not ridden it yet, the bike seems good to go. Thanks for the replies and recommendations.

    JT

  14. #14
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    Good unintended use of a tool

    Usually, if a crank becomes stuck in the way you describe, I would also have drilled out the bolt, but a tool for removing stripped crank arms does exist. I have to admit, your way has a much smaller chance of damaging either the frame or the crank arm.

  15. #15
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    Well, the drive-side crank bolt wasn't an issue; it didn't need to be drilled out. It was easy to remove. The problem was that the crank cap threads (M22) were stripped which prevented me from using a crank extracting tool. I have one but there was nothing for it to 'bite' into. so I threaded the crank bolt back in (just barely) and used that for the gear puller to push against the BB spindle.

  16. #16
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    Quote Originally Posted by beanbag View Post
    I doubt you stripped the threads on the spindle that the 8mm bolt grabs onto. That is hardened steel. I also doubt you stripped the threads on the 8mm bolt because that is hardened steel also.

    But you say the 8mm bolt turns freely, meaning that it is still trapped inside the crank arm, with the head hitting the 10mm nut? Fine, get a piece of metal, like a bolt, and drop it thru the spindle. unscrew the 8mm bolt on the drive side as much as possible. Hit the new bolt head with a hammer. This will push on your stripped 8mm bolt on the other side, which will push on the 10mm nut attached to the drive side crankarm.
    If this doesn't work, cut off the head on this bolt and make it shorter than the spindle. Then use the 8mm bolt on the other side to push on this new rod.
    That's a great idea, or a disastrous one. Depends on what is actually stripped or broken.

    OP, did you sheer the bolt off, does it spin that freely? You need to get the dust cap/extractor nut off the crank and see what your working with. If you can get the fixing bolt out you could replace it with something that is smaller but still catches the extractor nut and drive it out like beanbag suggested. Don't go down that path until your sure what is going on though.

  17. #17
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    Quote Originally Posted by Hobart View Post
    A new external BB and Truvativ Stylo crank are now installed using PLENTY of waterproof grease and eased in, then torqued.
    already installed. I have a drive side bb that i did not realize was reverse thread and did the same thing so i just pull the crank now and then, wipe out the bb ,grease it and hope it never fails

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