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105 pedal cracked bolt

craigus89craigus89 Posts: 887
edited October 2018 in Workshop
The 8mm allen bolt head on my 105 pedal has cracked with it stuck in the crank arm. I foolishly tightened the left side pedal rather than loosening it as it is reverse threaded (my excuses are that I was sleepy and 3 beers down) realised but had tightened it a bit much, tried to force it loose and cracked the bolt head. There are no flats on the spindle on the outer side of the crank arm so there is no way off getting this off.

I have to sacrifice the pedal anyway as it's broken, any easy way of getting this out of the crank arm? To make it more complicated it is stuck in my power meter crank arm which I assume (perhaps, hopefully wrongly) is a bit more delicate? I'm slightly hesitant to put it in a vice but maybe it will be fine. Any thoughts would be appreciated.

Also, why there are no flats on the spindle for removal of a stubborn pedal seems strange to me, is it just for a sleek look?

Posts

  • I have had this exact issue.

    1) Remove the pedal body from the spindle (there is a small nut against the pedal body you grip with a spanner)
    2) Take a file to the spindle to square off 2 opposite sides which can then be gripped with a vice of pair of pliers,
    3) Grip the spindle with vice and use crank arm to untwist.

    Pearson cycles in Sheen did it for me as they used their giant spinning sanding wheel to square off those 2 sides.

    Hope that makes sense.
  • MatthewfalleMatthewfalle Posts: 17,380
    If that doesn't work

    cut pedal off

    drill bolt head out of crank arm

    heli coil

    job jobbed
    Postby team47b » Sun Jun 28, 2015 11:53 am

    De Sisti wrote:
    This is one of the silliest threads I've come across. :lol:

    Recognition at last Matthew, well done!, a justified honour :D
    smithy21 wrote:

    He's right you know.
  • Vino'sGhostVino'sGhost Posts: 4,129
    If that doesn't work

    cut pedal off

    drill bolt head out of crank arm

    heli coil

    job jobbed

    thats not a simple / practical job for most home mechanics though. I did one like that recently, i couldnt even remove the pedal body it was all completely jiggered up. and i wasnt the first to have a go either, there were different pedals on the left and rh cranks.... whats more the hole for the hex key had been rounded off almost perfectly.

    It took ages, I ended up taking an angle grinder to the pedal.

    Then i had to get the lot set up in a bench drill, drilled out. havent cleaned up the hole yet. i need to find the correct bushing and taps etc but i cant imagine theyre either expensive or difficult to find. Its one of my many projects......

    The crank is not marked with a name but is solid (at least at the pedal end) I expect that it will be perfectly serviceable and the repair invisible once the pedal is fitted
    Happy days
  • keef66keef66 Posts: 13,123
    I think if you can remove the crank, dismantle the pedal, and clamp the spindle in a bench vice, you should be able to unscrew the crank from it without damaging the threads or the power meter.

    If you don't have the bench vice, leave it on the bike and grind some flats on the spindle so you can use an effing great adjustable wrench on it
  • craigus89craigus89 Posts: 887
    keef66 wrote:
    I think if you can remove the crank, dismantle the pedal, and clamp the spindle in a bench vice, you should be able to unscrew the crank from it without damaging the threads or the power meter.

    If you don't have the bench vice, leave it on the bike and grind some flats on the spindle so you can use an effing great adjustable wrench on it

    Yeah that's what I'm thinking at the moment. A mate has a proper home workshop so will pop over and get it done at some point. Hesitant to start drilling around the power meter crank if I'm honest, I don't know how they work but that really doesn't sound like a good idea.
  • Read what I wrote and follow the instructions.

    You cannot clamp the spindle in a vice, it will just turn. As you have broken the shoulders of the nut, it is more firmly lodged into the crank arm. You have to file the sides of the spindle flat so they can be gripped in a vice.

    It is very straightforward, but involves some effort and does not involve going near the crank arm with any power tools.
  • keef66keef66 Posts: 13,123
    You cannot clamp the spindle in a vice, it will just turn.

    Not if you completely dismantle the pedal. First you undo and remove the pedal body, then you remove the little cone + locknut from the end of the spindle and everything else including all the spinny bits should just slide off.

    The only complicating factor is remembering which way the various things turn...

    In which case the Dealer Manual is quite useful:

    http://si.shimano.com/pdfs/dm/DM-PD0002-07-ENG.pdf
  • craigus89craigus89 Posts: 887
    thanks Shirley and Keef. That is the method I'm planning to use, I think I've sourced the pedal assembly too so not a complete bin job which is good to know. I'll update with pics as it may be useful for others.
  • lesfirthlesfirth Posts: 1,356
    keef66 wrote:
    You cannot clamp the spindle in a vice, it will just turn.

    Not if you completely dismantle the pedal. First you undo and remove the pedal body, then you remove the little cone + locknut from the end of the spindle and everything else including all the spinny bits should just slide off.

    The only complicating factor is remembering which way the various things turn...

    In which case the Dealer Manual is quite useful:

    http://si.shimano.com/pdfs/dm/DM-PD0002-07-ENG.pdf

    As above. If the spindle turns in the vice tighten the vice more . If it still turns get a bigger or better vice.
  • NO THIS DOESNT WORK

    If you have cracked the bolt into the crank arm it will be too tight. The guy bent the vice arm.

    The spindle is too perfectly round to clamp in the vice.

    Sand down the sides first then it is dead easy.
  • vrsmattvrsmatt Posts: 156
    Drill a hole through the pedal spindle, insert sturdy screwdriver and undo.......
    Giant TCR Composite 1, Giant Defy Advanced 2, Boardman Comp, Santa Cruz Heckler, Raleigh M-Trax Ti, Strida LT, Giant Halfway
  • slowbikeslowbike Posts: 8,498
    NO THIS DOESNT WORK

    If you have cracked the bolt into the crank arm it will be too tight. The guy bent the vice arm.

    The spindle is too perfectly round to clamp in the vice.

    Sand down the sides first then it is dead easy.

    I must admit - I'd try just clamping the spindle first - I've done this on other stuck items - sometimes it works, sometimes it doesnt - if it doesn't then filing down is the obvious answer. But for 2 minutes trying - it's worth a try :)
  • Trust me I have tried. The guy hammered the vice arm with a hammer to get it tighter. Made no difference. Spindle continued to rotate in the vice's arms.

    Drilling a hole is an idea, but it would be bloody hard as the drill bit would slip off, plus you'd be pressed to find something that would fit through the middle that wouldn't break when force was applied.
  • It was bigger. The handle used to close the vice was much more heavy duty. The mechanic walloped it with a big hammer to make it tighter.

    Made no difference.
  • Get a garage to weld a plate to the pedal spindle. Then a vice can be used to do the rest. The spindle is steel so this is the simplest solution and will cost a tenner.
  • slowbikeslowbike Posts: 8,498
    Trust me I have tried. The guy hammered the vice arm with a hammer to get it tighter. Made no difference. Spindle continued to rotate in the vice's arms.
    Depends how "Stuck" it is - all we've got is that the head has cracked and the normal allen key won't work...
    Drilling a hole is an idea, but it would be bloody hard as the drill bit would slip off, plus you'd be pressed to find something that would fit through the middle that wouldn't break when force was applied.
    Ah - well .. you'd need to file a flat off first .... ... oh :o;)
  • N+1
  • Slowbike wrote:
    Trust me I have tried. The guy hammered the vice arm with a hammer to get it tighter. Made no difference. Spindle continued to rotate in the vice's arms.
    Depends how "Stuck" it is - all we've got is that the head has cracked and the normal allen key won't work...
    Drilling a hole is an idea, but it would be bloody hard as the drill bit would slip off, plus you'd be pressed to find something that would fit through the middle that wouldn't break when force was applied.
    Ah - well .. you'd need to file a flat off first .... ... oh :o;)

    If the head is cracked then you've over tightened. As the allen slot is well recessed into the bolt, it actually makes the thing even more stuck as it expands more tightly into where it is screwed.

    Remove pedal from spindle, flatten sides with file, grip flattened spindle in vice, use crank arm to unscrew.
  • slowbikeslowbike Posts: 8,498
    Slowbike wrote:
    Trust me I have tried. The guy hammered the vice arm with a hammer to get it tighter. Made no difference. Spindle continued to rotate in the vice's arms.
    Depends how "Stuck" it is - all we've got is that the head has cracked and the normal allen key won't work...
    Drilling a hole is an idea, but it would be bloody hard as the drill bit would slip off, plus you'd be pressed to find something that would fit through the middle that wouldn't break when force was applied.
    Ah - well .. you'd need to file a flat off first .... ... oh :o;)

    If the head is cracked then you've over tightened. As the allen slot is well recessed into the bolt, it actually makes the thing even more stuck as it expands more tightly into where it is screwed.

    Remove pedal from spindle, flatten sides with file, grip flattened spindle in vice, use crank arm to unscrew.

    I know ... I'd just try the grip in the vice first - if it didn't work, then go back to flattening the sides before attacking with a vice ... Having re-engined an MGB & a boat I'm pretty used to undoing the undoable - sometimes the shortcuts work - sometimes you have to do the longer method - the longer method usually works in the end - but you can save a lot of time if the shortcuts work...
  • svettysvetty Posts: 1,904
    gazza1286 wrote:
    Get a garage to weld a plate to the pedal spindle. Then a vice can be used to do the rest. The spindle is steel so this is the simplest solution and will cost a tenner.

    Heat conducted along crank arm might affect calibration of powermeter?
    FFS! Harden up and grow a pair :D
  • leave the pedals on the crank, job done.
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