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Unable to remove crank threads partially stripped

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Unable to remove crank threads partially stripped

Old 05-18-21, 05:01 PM
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tendency
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Unable to remove crank threads partially stripped

Hey all - new bike and when I went to take off the drive side crankarm found this:




Someone ground down the threads on the crankarm - aaaaargh! I'm unable to thread on the extractor tool .. what can I do to fix this?
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Old 05-18-21, 08:39 PM
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I made a thread chaser out of a broken crank extractor--cut some tap-like slots into the nut--and that works sometimes. Sometimes I can carefully repair the leading threads with a utility knife. If those tricks don't work I get out the pickle fork (automotive ball joint separator).
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Old 05-18-21, 08:43 PM
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Uhh, did you remove the crank fixing bolt (the hex head bolt in the middle of the opening) first before trying the extractor?
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Old 05-18-21, 09:00 PM
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tendency
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Originally Posted by HillRider View Post
Uhh, did you remove the crank fixing bolt (the hex head bolt in the middle of the opening) first before trying the extractor?
Yes, the pic was taken after I re-assembled - but thanks for checking
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Old 05-18-21, 09:01 PM
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Originally Posted by andrewclaus View Post
I made a thread chaser out of a broken crank extractor--cut some tap-like slots into the nut--and that works sometimes. Sometimes I can carefully repair the leading threads with a utility knife. If those tricks don't work I get out the pickle fork (automotive ball joint separator).
Cool thanks for tips - I'll see if I can fashion some sort of a thread chaser.
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Old 05-19-21, 12:21 AM
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failing that, a pulley remover rented from auto stores also works. you get your money back when you return the tool

like this....


Last edited by thook; 05-19-21 at 12:27 AM.
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Old 05-19-21, 03:14 AM
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i have never done this, just a hypothesis, remove the left hand crank, lock nut and cup,

now the rt crank can rest against the fixed rt cup, take off the bolt, remove the washer, put the bolt back in then back it out maybe 1/8th inch, put some pb blaster oil in there, or liquid wrench, get a drift punch or piece of round stock, tap on the spindle pretty good and see if it pops off,

or buy a bottom tap of the same thread size and chase it,
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Old 05-19-21, 05:08 AM
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Beaucoup threads on this.

Heat, 2 pickle forks, Jacobs chuck wedges are some of the methods to remove cranks with stripped out extractor threads.

Gear pullers generally haven't worked for me, but the one thook posted looks like it might have a chance of not slipping off. Put it on, get some tension on the arm, heat the arm with a heat gun, retension the puller, then tap the side of the crank arm sharply with a hammer to help vibrate everything loose.

If none of that works than break out the hacksaw...
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Old 05-19-21, 05:47 AM
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Originally Posted by tendency View Post
Cool thanks for tips - I'll see if I can fashion some sort of a thread chaser.
Bicycle Research made a crank thread chaser (below). The piece on the right is a pilot to keep the chaser on axis. The male end threads into a bolt-type spindle, the female end fits on a nut-type spindle. I suspect this tool has been out of production for a while. BikeToolsEtc offers a similar chaser, but without the pilot, so you'd need to be careful to keep the tool on axis.
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Old 05-19-21, 10:15 AM
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Originally Posted by Pop N Wood View Post
Beaucoup threads on this.

Heat, 2 pickle forks, Jacobs chuck wedges are some of the methods to remove cranks with stripped out extractor threads.

Gear pullers generally haven't worked for me, but the one thook posted looks like it might have a chance of not slipping off. Put it on, get some tension on the arm, heat the arm with a heat gun, retension the puller, then tap the side of the crank arm sharply with a hammer to help vibrate everything loose.

If none of that works than break out the hacksaw...
i had to use a puller once a long time ago to get a deore lx crank off a junky frame i found. i really wanted it because it was smoke colored. i did try a pickle fork, at first, but could quickly see it was only going to mar up the crank before it even came loose. anyway, i think the puller i used had better tabs at the arms' ends, and it worked very well without needing heat or hammer. that image was the only one i could find right away to illustrate, though.
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Old 05-19-21, 12:08 PM
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5-arm crank?
The generic pullers tend not to work well on those. They donít center right. If you insist, they tend to slip off under load. 3-arm pullers might do less poorly. Chuck wedges, pickle Forks work better. Or cutting the BB spindle.
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Old 05-19-21, 12:22 PM
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Chuck wedges. Do a search for them on BF.
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Old 05-19-21, 01:19 PM
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Originally Posted by genejockey View Post
Chuck wedges. Do a search for them on BF.

Chuck Norris wedges. Simply mention them in passing, and the crank will back itself off and apologize...
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Old 05-19-21, 03:27 PM
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Originally Posted by thook View Post
i did try a pickle fork, at first, but could quickly see it was only going to mar up the crank before it even came loose.
I've used a single pickle fork with some sheet metal shims to protect the bike, but someone on here suggested using two pickle forks. that would be most excellent. Pickle forks have the hammer helping to vibrate stuff loose as well.

I bought a set of Jacobs chucks but haven't had need for them yet. I replaced the 35 year old stripped out crank with a campy ultratorque unit. Crank extractors suck.
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Old 05-19-21, 03:55 PM
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Originally Posted by Pop N Wood View Post
I've used a single pickle fork with some sheet metal shims to protect the bike, but someone on here suggested using two pickle forks. that would be most excellent. Pickle forks have the hammer helping to vibrate stuff loose as well.

I bought a set of Jacobs chucks but haven't had need for them yet. I replaced the 35 year old stripped out crank with a campy ultratorque unit. Crank extractors suck.
Unless they work, then they're fantastic. But, yeah, when they fail, they really suck.
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Old 05-20-21, 02:16 AM
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another trick is to leave the bolt off and ride the bike for a while,

of course you want to monitor things closely so

1) you don't crash

2) you don't butcher the taper

and don't stray too far from home.
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