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How to remove a stripped crank bolt.

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How to remove a stripped crank bolt.

Old 02-24-08, 08:23 PM
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Cool_Man
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How to remove a stripped crank bolt.

Hello Folks.
Please give me some idea for removing a completely stripped crank bolt (drive side) on my Ultegra triple crank set, my lbs said that I may have to cut the crank arm to get to the bolt.
Andrew
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Old 02-24-08, 08:31 PM
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Is it the head of the bolt or the threads that are stripped?
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Old 02-24-08, 08:36 PM
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You might be able to drill it out...or cut a slot into it with a dremel tool. What type of bottom bracket is it? (Octalink/square taper/etc)
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Old 02-24-08, 08:45 PM
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It is an octalink BB, the head of the bolt is completely stripped, I over torqued the bolt now all I have is a round hole where the 8mm tool suppose to fit.
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Old 02-24-08, 08:58 PM
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That's actually better than if the threads were stripped. There are several options:

Buy a bolt extractor, drill out the bolt and remove it with the extractor, often called an EZ-out.

Drill off the head of the bolt, remove the crank with an extractor and remove the remainder of the bolt with a vice-grip.

Cut a slot in the head of the bolt with a cutoff tool, use an impact driver to remove the bolt.

If there's anything left of the hex at all, pound an SAE hex wrench into the bolt and try removing the bolt again.

Try a Torx wrench. They can often fit more tightly in a stripped hex.

Cut off the crankarm.
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Old 02-24-08, 10:16 PM
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Thanks for the tips.
I'll try the bolt extractor method first , if it does not work then I'll try to remove the crank arm then work on the bolt.
Andrew
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Old 02-24-08, 10:41 PM
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Originally Posted by Cool_Man View Post
Thanks for the tips.
I'll try the bolt extractor method first , if it does not work then I'll try to remove the crank arm then work on the bolt.
Andrew
Hey Andrew, you're welcome.

I'd still try anything you can before destroying the crank. It's brutal to deal with stripped components, but if you can save the crankarm, do it. Bolts are cheap and more easily replaced.
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Old 02-24-08, 11:21 PM
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Great suggestions but I'd try the 2nd method first. Drilling off the head and removing the crank first means that you have much less to lose once things get nasty. Also, if the bolt is so tight you stripped it trying to remove it, the EZ-out might not have enough grip either. Sometimes drilling out the center of the bolt will loosen it up but it's easier said than done to drill a straight hole all the way down the center of a hard bolt. Good luck no matter what route you take.
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Old 02-25-08, 05:01 AM
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No need to sacrifice the crank arm. Besides the great ideas above, you can also have someone TIG weld a bolt to the end of the octalink bolt head. Twist new bolt with box end wrench.
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Old 02-25-08, 05:44 AM
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Get a torx bit that wont quite fit into the rounded hole. Get one with a 3/8 drive that goes onto a ratchet wrench. Pound the bit into the hole with a hammer.Lay the opposite side crank on a block of wood while hammering to support it. This will ensure a tight fit and will also loosen the bolt. Remove the bolt with the ratchet. It should come right out.
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Old 01-02-15, 06:40 PM
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With some trepidation in reviving an old thread ... first I want to say thank you to all those above who posted suggestions.

The purpose of this post is to add my 2 cents for the benefit of others in the future who may Google and find this thread.

First, what DID NOT work for me is the following screw extractor. The extractor broke - not near man enough for the job.



What DID work for me is the following extractor with a 1/2" drive 18" long breaker bar and socket. Bought the package of 5 extractors for $9.99 at Princess Auto. I had to drill out the center of the bolt to make the hole deep enough for the extractor to engage.



Lastly, another tip that I gleaned from the interweb is using a skewer to keep the bottom bracket tool engaged leaving both hands free to apply the brute force needed to loosen it.

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Old 01-02-15, 06:55 PM
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EZ-Out; and sometimes you can buy them in a kit with a left rotating drill bit. Some times the bolt comes right out with the drill bit before you even get a chance to use the EZ-Out. I think the heat from the drilling process has something to do with it. But for your purpose if I'm picturing what you're doing correctly an EZ-Out and a left rotating bit slightly smaller than the bolt OD is what you'd want.
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Old 01-02-15, 06:57 PM
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As long as we are resurrecting a real old thread, note that Ultegra and Dura Ace Octalink cranks (FC6500, FC6503, FC7700) had autoextractor bolts. There is a collar with two spanner holes that screws into the crank extractor threads around the fixing bolt. The proper removal technique is to loosen the center bolt with an 8 mm hex wrench a turn or so to where it will get tight again as it comes up against the outer collar. Continuing to turn the bolt will press the arm off of the bb spindle.

One more thing; make sure the 8 mm bit or hex key you use is in good condition with sharp corners. A worn, loose key will cause just the problem that started this thread.
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Old 01-02-15, 07:33 PM
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Originally Posted by h2oxtc View Post
With some trepidation in reviving an old thread ... first I want to say thank you to all those above who posted suggestions.

The purpose of this post is to add my 2 cents for the benefit of others in the future who may Google and find this thread.

First, what DID NOT work for me is the following screw extractor. The extractor broke - not near man enough for the job.



What DID work for me is the following extractor with a 1/2" drive 18" long breaker bar and socket. Bought the package of 5 extractors for $9.99 at Princess Auto. I had to drill out the center of the bolt to make the hole deep enough for the extractor to engage.



Lastly, another tip that I gleaned from the interweb is using a skewer to keep the bottom bracket tool engaged leaving both hands free to apply the brute force needed to loosen it.

Here's something I picked up at Princess Auto a while back for just such eventualities.
9 pc Metric Extractor End Hex Key Set | Princess Auto
Have not had the opportunity to test it yet, so I can't offer a report.
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Old 01-02-15, 07:43 PM
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can't decide whether it's optimistic or pessimistic to buy a stripped bolt extractor tool before needing one.
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Old 01-02-15, 09:59 PM
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Originally Posted by hueyhoolihan View Post
can't decide whether it's optimistic or pessimistic to buy a stripped bolt extractor tool before needing one.
It's neither, it's preventative. If you have one you will never need it. If you don't have one you will need it desperately just when all the shops are closed for a 3-day holiday.
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Old 01-02-15, 10:06 PM
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i see... so it's not like a tire patching kit. because i carry one and i'm still getting flats.
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Old 01-03-15, 12:48 AM
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had this same problem working on this rust bucket the other day

first the plastic screw in dust cover wouldn't screw off, spent about an hour digging that out
..to discover the crank tention nut was a bit on the round side, ended up using a smaller socket..belted that in..lucky it had enough grip to u-do {then had to belt the nut out of the socket**
all this to try and save the crank, but *sigh* that had a stripped thread, ended up cutting that off with angle grinder
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Old 01-03-15, 10:04 AM
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Originally Posted by koolerb View Post
EZ-Out; But for your purpose if I'm picturing what you're doing correctly an EZ-Out and a left rotating bit slightly smaller than the bolt OD is what you'd want.
That's exactly what I'm picturing. The first one was too small for the job and broke.

Originally Posted by HillRider View Post
As long as we are resurrecting a real old thread, note that Ultegra and Dura Ace Octalink cranks (FC6500, FC6503, FC7700) had autoextractor bolts. There is a collar with two spanner holes that screws into the crank extractor threads around the fixing bolt. The proper removal technique is to loosen the center bolt with an 8 mm hex wrench a turn or so to where it will get tight again as it comes up against the outer collar. Continuing to turn the bolt will press the arm off of the bb spindle.

One more thing; make sure the 8 mm bit or hex key you use is in good condition with sharp corners. A worn, loose key will cause just the problem that started this thread.
I discovered the auto-extractor bolts in my online research, in fact that's what the new cranks have. The original, stuck bolts, were not. Interesting comment about the hex keys - it's possible that the previous owner may have partially stripped the bolts in a previous attempt as the hex wrench was loose right from the start. I tried using three 8mm wrenches - so I know it wasn't the wrenches.

Originally Posted by Dan Burkhart View Post
Here's something I picked up at Princess Auto a while back for just such eventualities.
9 pc Metric Extractor End Hex Key Set | Princess Auto
Have not had the opportunity to test it yet, so I can't offer a report.
Dan, thanks for the suggestion. I saw these on the rack when I was looking for the extractors. They do indeed look useful, however in my situation I needed the leverage of the breaker bar to get the bolts to move.

I'm beginning to learn that you can never have too many tools. Preventative or not. I'm beginning to need something / someplace to keep all the tools so that I can find them. But that's a different thread.
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Old 01-03-15, 12:28 PM
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When faced with a stripped crank bolt head, and after no success by other means, I picked up a Craftsman Bolt-Out kit

...and removed it in a jiffy.
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