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Thread: Frozen bottom bracket!!

  1. #1
    Join Date
    Jul 2008
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    Dillon, CO
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    Frozen bottom bracket!!

    Any pro tips on how to get it off (bottom bracket)? The bike is only about a year old, but the bb is toast. It is a square taper cartridge. The driveline side has a lip that is flush with the frame. the side opposite of the driveline has threads poking out. I have torqued it, used penetrating spray, and even an impact driver to no avail. I am frustrated and pissed. What say you mags?

  2. #2
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    Mar 2007
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    I had the same problem with a BB last summer. Impact wrench did nothing, we used penetrating spray, etc. What finally got it loose is we stripped the frame down, I used the frame itself for leverage and my dad used a 4 way breaker bar to turn the tool against the direction I turned the frame. We also used a heat gun to warm up the frame. Finally we got it out.
    All I know is that I don't know nothin'... and that's fine.

  3. #3
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    Sep 2005
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    Canadian Rockies
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    ^^^^^^ Heat gun for the hopeful win...

  4. #4
    Join Date
    Jul 2008
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    Heat and leverage FTW! Thanks. What a piece of shit chinese part...that doesnt leave many options for replacement.

  5. #5
    Join Date
    Mar 2010
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    Electric Larry Land
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    This can be used for pretty much ANY frozen metal parts...on a bike, truck, horse trailer, whatever:

    Forget the heat gun...you need a propane torch. When heating up the offending piece, make sure you only apply direct heat to ONE surface. I.E. - for bottom bracket, heat up the metal surrounding the bracket. At the same time, gently (or not so gently), tap on the bracket with a bronze drive. Tap some more and you should be able to break whattever bonds (grit, rust or both) are holding it, and wrench it out as normal.

    This all is helped by soaking the damn thing in PB Blaster for like a week.

    When you go to put in the new bottom bracket, make sure you use a very high-quality water-proof grease...this will make it easier to take the BB off next time. BBs get a LOT of abuse from road grime, mud, salt-water, stream water etc....that is why they're like a WITCH to get out !!!
    "The reason death sticks so closely to life isn't biological necessity - it's envy. Life is so beautiful that death has fallen in love with it; a jealous, possesive love that grabs at what it can." by Yann Martel from Life of Pi



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  6. #6
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    Quote Originally Posted by Alaskan Rover View Post
    This can be used for pretty much ANY frozen metal parts...on a bike, truck, horse trailer, whatever:

    Forget the heat gun...you need a propane torch. When heating up the offending piece, make sure you only apply direct heat to ONE surface. I.E. - for bottom bracket, heat up the metal surrounding the bracket. At the same time, gently (or not so gently), tap on the bracket with a bronze drive. Tap some more and you should be able to break whattever bonds (grit, rust or both) are holding it, and wrench it out as normal.

    This all is helped by soaking the damn thing in PB Blaster for like a week.

    When you go to put in the new bottom bracket, make sure you use a very high-quality water-proof grease...this will make it easier to take the BB off next time. BBs get a LOT of abuse from road grime, mud, salt-water, stream water etc....that is why they're like a WITCH to get out !!!
    I'm pretty sure you would fuck up the heat treatment of the frame doing this. Not to mention the paint.
    All I know is that I don't know nothin'... and that's fine.

  7. #7
    Join Date
    May 2010
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    where the rough and fluff live
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    I would think Cold would work a lot better than Heat, to reduce the friction. Maybe I'm nutty, but let me explain why: Heat would help penetrating oil get into more spots. But... Cold would shrink the metal giving more space.

    Most people have heat sources, and not big chest freezers that can hold a frame, so this might explain why more think Heat and not Cold.

    It's not temperature-based "frozen" in there. It's mechanically frozen, through friction.

    Remember: some suspension forks get cryofit crowns... shrink them under cold, assemble, then at room temperature they're stuck as if glued, bonded, they're mechanically adhered.

  8. #8
    Join Date
    Oct 2007
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    As CF said...if you really want to get nerdy, dry ice inside the cup is technically the correct way to use temperature to free the part...shrink the cup but not the shell

    but since the metals will probably expand and contract at different rates, heating the whole mess and then letting it cool down usually does the trick
    The killer awoke before dawn.
    He put his boots on.

  9. #9
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    We're talking about heating the BB shell, not the BB itself. Yes obviously the BB itself will get heated through conduction, but not as much as the shell will, so the expansion rates should be different, thus making it easier to remove. If I could get dry ice into a sealed BB, then I probably wouldn't be having problems removing it. Chilling the BB shell around the BB seems like the worst possible idea. Aluminum has a much higher thermal expansion coefficient then steel, and thus greater expansion (and contraction) rates. So basically, chilling the bb shell will make it much harder to remove.
    All I know is that I don't know nothin'... and that's fine.

  10. #10
    Join Date
    Oct 2008
    Posts
    376
    Bring it to a good lbs. they will have a bb tool that threads into the bb where the crank is installed and then you will be able to use a pipe and put lots of leverage on the tool without fear of the tool popping out and wrecking the bb.

  11. #11
    Join Date
    Oct 2008
    Posts
    376
    if that doesn't get, spray some kroil and let it seep in for a bit then try again. i wouldn't recommend heating.

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