I want to replace the bottom-bracket bearings but the drive-side crank won't come off. It's been stuck for about five years when it resisted the best efforts of The Bicycleworks to shift it. It's a Dura Ace crank on an Octalink spline. It has a self-extracting bolt which is rounded to the point of being unusable. Is there any other way of getting this off than resorting to an angle-grinder as TBW suggested? I don't care about destroying the crank or the bearing but I want to avoid damaging the frame in any way.
CityCyclingEdinburgh Forum » Questions/Support/Help
Removing a seized crank
(14 posts)- Started 10 years ago by Cyclingmollie
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Posted 10 years ago #
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"Is there any other way of getting this off than resorting to an angle-grinder as TBW suggested? I don't care about destroying the crank or the bearing but I want to avoid damaging the frame in any way."
Hacksaw - if you're worried about grinder slipping.
Probably take about 20 mins.
Probably best with bike upside down.
Maybe use grinder first and finish with (small?) saw.
If you get completely through crank 'should' come off.
May need two cuts to remove a chunk.
Posted 10 years ago # -
My stuck fasteners treatment plan;
1) Penetrating lubricant left to soak in.
2) Use of stud extractor if applicable (you may borrow mine)
3) Grind a flat or cut a slot in the head if it's rounded off (Dreml be your friend)
4) Heat the female part
5) Freeze the male part
6) Drill a hole in the fixer, tap a reverse thread in it and use a reverse-thread bolt to unscrew the original fixer (unlikely to be cost-effective on a bicycle)Posted 10 years ago # -
Thank you. TBW had the crank extractor tool in a vice using the bike as a lever and it still wouldn't shift so bolt extractor and penetrating fluid may not be enough. Ditto freezing the crank which would still need the bolt extractor. I'm tempted to try the hacksaw. I have one and it requires no skill and lots of effort which is something I'm used to.
Posted 10 years ago # -
I have a few different extractor tools for removing Octalink cranks if you want to pop round and give them a go to see if it'll shift before resorting to a saw.
Posted 10 years ago # -
If you're round the south side of town you can spin by and I'll cut flats on the bolt with a diamond disc on the Dreml. Much easier than a hacksaw....but does sound like it's proper welded.
Posted 10 years ago # -
Thank you IWRATS. I fear it is totally unmoveable. Cyclops I will do that but will pay for your professional work of course - even if it doesn't come off without sawing.
Posted 10 years ago # -
I took the bike to Cyclops who confirmed the crank was stuck and cut it off with a saw, cleaned out the threads and faced the BB shell (which had never been done before). Nice job.
Posted 10 years ago # -
"cut off the crank"
What with?
Was one cut enough?
Posted 10 years ago # -
Posted 10 years ago #
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That's a bit extreme!
(You didn't answer the first question.)
Posted 10 years ago # -
I think it was a hacksaw rather than a power-tool. Cyclops didn't want to risk a powered saw slipping and damaging the frame. I didn't stay to watch. Also Mrs Cyclops' raspberry and white chocolate muffins are very good.
Posted 10 years ago # -
I can confirm it was a hacksaw. I didn't have to quite cut all the way through the crank as once I'd cut through the bolt I could wiggle out the two halves of it and remove the crank with an extractor.
Posted 10 years ago # -
Thanks.
Posted 10 years ago #
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