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Stuck crank blues

Started by Simon Brooke · · Last activity · 19 posts · 767 views

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UK and Europe
Published
17 August 2005
Last activity
18 August 2005
Original author
Simon Brooke
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19
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  1. OK, people, let's have your favourite cures for stuck cranks. I am faced
    with a Halfords Carrera hardtail. It has a horrible irregular noise from
    the bottom bracket when pedalling - so horrible that I first suspected a
    cracked frame, but I can't find any cracks. The bottom bracket axle is a
    bit loose - not so much so that I can be certain there's something
    horribly wrong with it, but it does have to be checked.

    So I have to get the cranks off. And I have just wrecked a brand new
    crank tool trying. I _think_ the bottom bracket is square taper but to
    be honest can't see enough with the cranks on to be absolutely certain.
    It's the relatively modern sort of bottom bracket where the cranks are
    held on with allen head bolts which screw into the ends of the bottom
    bracket spindle. I have tried the usual tricks - heating the cranks with
    a blowtorch, wellying it with a rubber mallet - and absolutely no
    movement at all. I don't particularly want to wreck the crankset, but if
    I can't sort the problem the bike is scrap anyway.

    Suggestions? Wizard wheezes?

    --
    [email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

    For office use only. Please do not write or type below this line.

  2. Simon Brooke said:

    OK, people, let's have your favourite cures for stuck cranks.

    Repeated applications of WD40, letting it wait overnight before
    attempting removal.

    Are you sure you've extracted *all* of each allan bolt? No bit sheared
    off the end?

    R.

  3. "Simon Brooke" <[email hidden]> wrote in message
    news:[email hidden]...

    Quoted message said:

    So I have to get the cranks off. And I have just wrecked a brand new
    crank tool trying. I _think_ the bottom bracket is square taper but to
    be honest can't see enough with the cranks on to be absolutely certain.
    It's the relatively modern sort of bottom bracket where the cranks are
    held on with allen head bolts which screw into the ends of the bottom
    bracket spindle. I have tried the usual tricks - heating the cranks with
    a blowtorch, wellying it with a rubber mallet - and absolutely no
    movement at all. I don't particularly want to wreck the crankset, but if
    I can't sort the problem the bike is scrap anyway.

    Suggestions? Wizard wheezes?

    I've never had joy with hitting or heating. What has worked for me is
    building a puller out of bits of metal and bolts which pulls behind the
    crank.

    Mine is in nasty mild steel, so has a tendancy to bend, so there's an old
    crank providing support on the outside. So far it's worked before the bits
    behind have bent sufficiently far to be unusable.

    Interesting that you wrecked the crank tool rather than the crank though...

    cheers,
    clive

  4. Simon Brooke said:

    OK, people, let's have your favourite cures for stuck cranks. I am faced
    with a Halfords Carrera hardtail. It has a horrible irregular noise from
    the bottom bracket when pedalling - so horrible that I first suspected a
    cracked frame, but I can't find any cracks. The bottom bracket axle is a
    bit loose - not so much so that I can be certain there's something
    horribly wrong with it, but it does have to be checked.

    So I have to get the cranks off. And I have just wrecked a brand new
    crank tool trying. I _think_ the bottom bracket is square taper but to
    be honest can't see enough with the cranks on to be absolutely certain.
    It's the relatively modern sort of bottom bracket where the cranks are
    held on with allen head bolts which screw into the ends of the bottom
    bracket spindle. I have tried the usual tricks - heating the cranks with
    a blowtorch, wellying it with a rubber mallet - and absolutely no
    movement at all. I don't particularly want to wreck the crankset, but if
    I can't sort the problem the bike is scrap anyway.

    So you have taken the bolts out and trashed a crank tool? surely you
    would have stripped the crank threads first? in which case they are
    toast - gas axe time.

    A ball joint extractor may be a useful thing for this.. couple of
    prongs to go under the crank and a screw thread to push the joint
    apart. Failing that the other sort which look like a bolster chisel
    with a cutout could be used. And if that fails, use a cold chisel to
    split the crank.

    Other option.. lay bike on side. Pour coca cola into the crank. Leave a
    day and then try again.

    Other option 2. Leave the bolt out. Take it for a spin in the hills.

    ...d

  5. As someone has already posted, if you've removed the allen bolts
    already from the cranks and then broken a crank tool, you may have
    already knackered the crank threads beyond all hope.

    If you can't get an allen bolt out, is it possible you're winding the
    wrong way? Doesn't one (the none-drive side bolt, I think) thread the
    opposite way?

    Nick

  6. Simon Brooke said:

    I have tried the usual tricks - heating the cranks with
    a blowtorch, wellying it with a rubber mallet - and absolutely no
    movement at all. I don't particularly want to wreck the crankset,
    but if I can't sort the problem the bike is scrap anyway.

    Suggestions? Wizard wheezes?

    Have you tried saying "bugger"?

    Method 1. If you've got a motor car type hub puller or gear extractor
    in your took kit you may be able to use that, possibly with a bit of
    ingenuity required in getting it to grip behind the crank.

    Method 2. Put crank in bench vice and use a punch to knock the spindle,
    and the rest of the bike, out of the crank. The alternative of grasping
    the frame firmly with both hands, placing the soles of the feet through
    the frame and onto the bench either side of the vice and heaving like a
    looney may appear tempting, but even with mattresses on the floor may
    lead to serious injury.

    Method 3. Leave the allen bolt out and go for a ride. If it's a square
    taper it should work loose, without injuring you hopefully, otherwise
    it probably won't. If you do manage to work the crank loose this way,
    it's toast even if it looks undamaged.

    Method 4. Failing all of the above, I think you might have to saw the
    crank off. Sawing through the crank will be much easier than through
    the BB spindle. If you cut a big slot towards the spindle you should be
    able to split the crank with a cold chisel.

    --
    Dave...

  7. NickD said:

    If you can't get an allen bolt out, is it possible you're winding
    the wrong way? Doesn't one (the none-drive side bolt, I think)
    thread the opposite way?

    No.

    --
    Dave...

  8. I said:

    If you've got a motor car type hub puller or gear extractor
    in your took kit you may be able to use that...

    That was meant to be /tool/ kit of course, though if you've acquired
    some of your favourite tools by the tradional method took kit may well
    be appropriate.

    --
    Dave...

  9. David Martin said:


    So you have taken the bolts out and trashed a crank tool? surely you
    would have stripped the crank threads first? in which case they are
    toast - gas axe time.

    I've done this as well. Very corroded on crank on old bike, not very clean threads.

    Result : one buggered crank tool and one buggered crank.

    If it was me I'd just get a hacksaw and remove the cranks with that.

    Arthur

    --
    Arthur Clune PGP/GPG Key: http://www.clune.org/pubkey.txt
    The struggle of people against power is the struggle
    of memory against forgetting - Milan Kundera

  10. "Simon Brooke" <[email hidden]> wrote in message
    news:[email hidden]...

    Quoted message said:

    Suggestions? Wizard wheezes?

    Oh yes - forgot another one I've done successfully. Cut the BB axle (I used
    an angle grinder, but this probably only works on non-drive side).

    cheers,
    clive

  11. Simon Brooke said:

    So I have to get the cranks off. And I have just wrecked a brand new
    crank tool trying. I _think_ the bottom bracket is square taper but to
    be honest can't see enough with the cranks on to be absolutely certain.


    ~~~~~~~~

    Are you sure you didn't leave the crankbolt washer in there? This would
    explain
    a why you can't see the axle end
    b why the puller destroyed itself

    --
    ---
    Marten Gerritsen

    INFOapestaartjeM-GINEERINGpuntNL
    www.m-gineering.nl

  12. in message <[email hidden]>, NickD

    (') said:

    As someone has already posted, if you've removed the allen bolts
    already from the cranks and then broken a crank tool, you may have
    already knackered the crank threads beyond all hope.

    Surprisingly, not. I have done that to cranks in the past, but not this
    time, it appears.

    Quoted message said:

    If you can't get an allen bolt out, is it possible you're winding the
    wrong way? Doesn't one (the none-drive side bolt, I think) thread the
    opposite way?

    No. Having now got the cranks and the NDS of the bottom bracket off, I've
    now got the problem of getting the drive side off, which almost
    certainly is a left hand thread. It has Shimano-type internal splines,
    but doesn't /quite/ fit my Shimano tool, so I don't want to try using
    any force for fear of damaging the splines on the tool. Still, welly
    with an old screwdriver will probably do it...

    Thanks for the suggestions, though.

    --
    [email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/
    There's nae Gods, an there's precious few heroes
    but there's plenty on the dole in th Land o th Leal;
    And it's time now, tae sweep the future clear o
    th lies o a past that we know wis never real.

  13. Simon Brooke said:

    So I have to get the cranks off. And I have just wrecked a brand new
    crank tool trying. I _think_ the bottom bracket is square taper but to
    be honest can't see enough with the cranks on to be absolutely
    certain. It's the relatively modern sort of bottom bracket where the
    cranks are held on with allen head bolts which screw into the ends of
    the bottom bracket spindle. I have tried the usual tricks - heating
    the cranks with a blowtorch, wellying it with a rubber mallet - and
    absolutely no movement at all. I don't particularly want to wreck the
    crankset, but if I can't sort the problem the bike is scrap anyway.

    An automotive gear puller, perhaps aided by the blowtorch?

    --
    Wally
    www.artbywally.com
    www.wally.myby.co.uk

  14. in message <[email hidden]>, Clive

    George (') said:

    "Simon Brooke" <[email hidden]> wrote in message
    news:[email hidden]...

    Quoted message said:

    So I have to get the cranks off. And I have just wrecked a brand new
    crank tool trying. I _think_ the bottom bracket is square taper but to
    be honest can't see enough with the cranks on to be absolutely
    certain. It's the relatively modern sort of bottom bracket where the
    cranks are held on with allen head bolts which screw into the ends of
    the bottom bracket spindle. I have tried the usual tricks - heating
    the cranks with a blowtorch, wellying it with a rubber mallet - and
    absolutely no movement at all. I don't particularly want to wreck the
    crankset, but if I can't sort the problem the bike is scrap anyway.

    Suggestions? Wizard wheezes?

    I've never had joy with hitting or heating. What has worked for me is
    building a puller out of bits of metal and bolts which pulls behind the
    crank.

    Mine is in nasty mild steel, so has a tendancy to bend, so there's an
    old crank providing support on the outside. So far it's worked before
    the bits behind have bent sufficiently far to be unusable.

    Interesting that you wrecked the crank tool rather than the crank
    though...

    The crank tool pin had a sort of rotating collar on the business end.
    This was a slight interference fit in the small end of the square taper
    in the crank, and jammed there. When I unscrewed the pin, the collar
    remained in the crank. B%&&£r! Still, after a marinade in plus-gas and
    the application of extreme ignorance, the blasted thing is now off.

    --
    [email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

    ;; Human history becomes more and more a race between
    ;; education and catastrophe.
    H.G. Wells, "The Outline of History"

  15. in message <[email hidden]>, m-gineering

    (') said:
    Simon Brooke said:

    So I have to get the cranks off. And I have just wrecked a brand new
    crank tool trying. I _think_ the bottom bracket is square taper but to
    be honest can't see enough with the cranks on to be absolutely
    certain.


    ~~~~~~~~

    Are you sure you didn't leave the crankbolt washer in there? This would
    explain
    a why you can't see the axle end
    b why the puller destroyed itself

    Yup, certain. They're now off - a combination of marinading in plus gas
    and wellying /really/ hard with the rubber mallet... in the course of
    which I managed to catch my finger a good solid blow. %^&*$&&%$&%$%$^!

    Thanks for all the suggestions, everyone.

    --
    [email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

    ;; Want to know what SCO stands for?
    ;; http://ars.userfriendly.org/cartoons/?id=20030605

  16. On 17 Aug 2005 08:42:03 -0700, "dkahn400" <[email hidden]>

    Quoted message said:
    I said:

    If you've got a motor car type hub puller or gear extractor
    in your took kit you may be able to use that...

    That was meant to be /tool/ kit of course, though if you've acquired
    some of your favourite tools by the tradional method took kit may well
    be appropriate.

    I thought I had one but Peregrine Took it.

    Tony

  17. Simon Brooke said:

    So I have to get the cranks off. And I have just wrecked a brand new
    crank tool trying. I _think_ the bottom bracket is square taper but to
    be honest can't see enough with the cranks on to be absolutely certain.

    That should be obvious the hole is huge in the octalink types.

    http://www.sheldonbrown.com/gloss_sp-ss.html#spline

    Also a normal crank extractor won't work in one.

    Steve

  18. Simon Brooke said:

    No. Having now got the cranks and the NDS of the bottom bracket off, I've
    now got the problem of getting the drive side off, which almost
    certainly is a left hand thread. It has Shimano-type internal splines,
    but doesn't /quite/ fit my Shimano tool, so I don't want to try using
    any force for fear of damaging the splines on the tool. Still, welly
    with an old screwdriver will probably do it...

    Is it a real Shimano tool or a Shimano-fit tool? I have both and the
    non-Shimano one won't sit over some deeper BB's and therefore cannot
    remove them.

    If it is a plastic BB then you could do really nasty things with a
    screwdriver to it. Failing that, slightly misaligned splines will only
    damage teh plastic, not the BB tool.

    If metal, then the same plusgas/heat/welly should do it. You migt want
    to try placing a drift of some sort against the BB and giving it very
    sharp taps with a *small* hammer to fracture any corrosion and free the
    threads.

    ...d

    ps. Trailer coming along nicely.. waiting for a hitch from Weber (via
    EBC, very good service.) Lesson #359. Work on the end of the tube away
    form you first as leaning over a red hot workpiece will set your
    overalls on fire.

  19. Tony said:

    I thought I had one but Peregrine Took it.

    As long as he doesn't make a hobbit of it.

    --
    Dave...

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