Can't get my crank off
06 March 2012, 04:57 PM
#1
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Can't get my crank off
The bottom bracket bearing is either loose or knackered. I've bought a crank extractor but the bloody thing isn't shifting. I've dowsed the area with releasing spray and to cap it all, I think I've stripped the threads off one of the cranks.
Can anyone help before I give up and wheel the thing down to the LBS.
Ta
Steve
Can anyone help before I give up and wheel the thing down to the LBS.
Ta
Steve
06 March 2012, 05:46 PM
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What sort of BB standard is it?
Hold your horses until you tell us.
If it is something like Hollowtech II the cup on the drive side is left hand thread, the other side is right hand.
EDIT - Not sure what you mean exactly? The cups won't come off or you can't get the crank so slide out the drive side - which implies an outboard system like hollowtech II? You know with hollowtech II you need to back off the plastic star thingy on the non-drive side before the non-drive side crank will slide off along the splines. You need to loosen the two pinch bolts to do this too. Get a rubber mallet and hammer it too.
Hold your horses until you tell us.
If it is something like Hollowtech II the cup on the drive side is left hand thread, the other side is right hand.
EDIT - Not sure what you mean exactly? The cups won't come off or you can't get the crank so slide out the drive side - which implies an outboard system like hollowtech II? You know with hollowtech II you need to back off the plastic star thingy on the non-drive side before the non-drive side crank will slide off along the splines. You need to loosen the two pinch bolts to do this too. Get a rubber mallet and hammer it too.
Last edited by tony de wonderful; 06 March 2012 at 05:57 PM.
06 March 2012, 06:17 PM
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06 March 2012, 06:23 PM
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Thanks!
Sadly, I am doing everything correctly but the bloody thing is just stuck tight. I either need a bigger hammer or a bigger lever.
Steve
Sadly, I am doing everything correctly but the bloody thing is just stuck tight. I either need a bigger hammer or a bigger lever.
Steve
06 March 2012, 06:49 PM
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06 March 2012, 07:19 PM
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Should work. Get a cheater bar on it. Just make sure the outer housing thingy is screwed in all the way before you apply massive torque.
It works believe me. I saved the day a few times when I used to run downhole instrumentation. Things supposed to break at 50 ft/lbs would get stuck after vibration and solids exposure. WD40 will only do so much. A massive cheater bar and hang your weight off it is the only way to go. I once had to get a forklift to pull on something once as it was stuck. Nothing can resist that sort of torque!
It works believe me. I saved the day a few times when I used to run downhole instrumentation. Things supposed to break at 50 ft/lbs would get stuck after vibration and solids exposure. WD40 will only do so much. A massive cheater bar and hang your weight off it is the only way to go. I once had to get a forklift to pull on something once as it was stuck. Nothing can resist that sort of torque!
06 March 2012, 07:22 PM
#13
When using the crank extractor tool, ENSURE THAT IT'S TIP WILL FIT INTO THE SQUARE OF THE CRANK ARM WITHOUT FOULING, BUT WILL NOT GO INTO THE THREADS ON THE END OF THE AXLE.
ie: it MUST clear the cranks but it must bear onto the bottom bracket axle.
On one I used to have, I had to insert a bolt loosely into the axle threads to allow the crank puller to bear on it.
It LOOKS like yours is touching the sides of the crank square, look at pic 2.
ie: it MUST clear the cranks but it must bear onto the bottom bracket axle.
On one I used to have, I had to insert a bolt loosely into the axle threads to allow the crank puller to bear on it.
It LOOKS like yours is touching the sides of the crank square, look at pic 2.
06 March 2012, 07:35 PM
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The centre bit must butt up against the bottom bracket without touching any of the crank arm. As alcazar says it looks like the tool's been touching the inside of the crank arm.
06 March 2012, 07:35 PM
#17
It looks like something round has been pressing against the square taper of the crank arm and raised some islands of alloy as Alcazar says.......you need to double check that it's sitting against the steel axle.........
Just checked and this is eactly as posted......... I'll get my coat LOL
Shaun
Just checked and this is eactly as posted......... I'll get my coat LOL
Shaun
06 March 2012, 07:48 PM
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Can you drive anything wedge shaped between the crank arm and whatever's behind it (I think it's normally just a bit of bottom bracket) maybe a large screwdriver end to pre-load the crank arm, then try and wind it off?
Maybe try to get something down each side of the central square to even the pressure up.
If you see what I mean
Maybe try to get something down each side of the central square to even the pressure up.
If you see what I mean
06 March 2012, 07:55 PM
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Looks like a weekend job now as I'm on the silly o'clock flight to Aberdeen in the morning. My brother in law is visiting on Sunday. I think he may be getting skinned knuckles 
Steve
Steve
06 March 2012, 08:00 PM
#21
Nothing can improve on the pressure from the crank extractor, everything else likely damages the alloy crank arm........check the extractor is fully home and the centre bolt does not foul the crank arm and use additional pressure.....
Shaun
Shaun
06 March 2012, 09:24 PM
#23
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07 March 2012, 10:26 AM
#29
Last time I struggled to get the crank off a bike I used: penetrating oil (for a few hours at least) a bolt of the same thread (inserted all the way), a small bearing puller, a drift and a lump hammer!
It was well stuck and rusted in, but after some beating it eventually relented.
Edit: Actually, thinking back, I think I failed to succreed with the bearing puller, and put the crank in a large vice (bike still attached) and lamped the inserted bolt with the lump hammer. Sorry, my memory is a bit rusty as I stopped messing with bikes when I bought a car
This was on a crappy Emmelle with 2mm of bearing play though
It was well stuck and rusted in, but after some beating it eventually relented.
Edit: Actually, thinking back, I think I failed to succreed with the bearing puller, and put the crank in a large vice (bike still attached) and lamped the inserted bolt with the lump hammer. Sorry, my memory is a bit rusty as I stopped messing with bikes when I bought a car
This was on a crappy Emmelle with 2mm of bearing play though
Last edited by ALi-B; 07 March 2012 at 10:36 AM. Reason: Forgot the bearing puller!