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square taper crank frozen, how to remove?

Old 10-22-14, 08:53 PM
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Gresp15C
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square taper crank frozen, how to remove?

I've done this a few time before on other bikes. This time, a 20+ year old bike that's probably never been serviced. Aluminum crank, square taper. I can't get it to budge. I've got one of those two piece crank pullers that you turn with a regular wrench. I support the crank end on a wood block and push down with a pretty long wrench.

Can I apply penetrating oil, and will it help? These bearings need to be repacked, as the crank feels pretty sticky when I turn it with the chain off.

It's been a week of bike repairs... rebuilding the Sturmey Archer, replacing a worn out rim on one bike, and getting another bike into riding shape after a long time in storage.
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Old 10-22-14, 09:20 PM
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Here's a trick that sometimes works, especially if the crank remover has somewhat sloppy threads.

What follows assumes that it's not something dumb like the plunger being too big for the square hole.

Thread the remover body to the bottom then back off 1/2 turn. Thread plunger in and tighten until it gets very hard to turn. Now get a decently heavy hammer, and deliver a solid blow to the back end of the pusher bolt. This can advance it within the slop in the threads, often breaks any bond holding the parts. Return to turning the bolt and see if it's now ready to come apart.

BTW- this shouldn't be used as SOP, and reserved for only those situations that call for it. I usually use it if someone shows me a crank remover that broke.

If that fails, the 100% never fails surefire method is with a pair of Jacobs chuck wedges. Chuck wedges have been my fallback for stripped cranks for over 40 years and have never let me down.
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Old 10-22-14, 09:26 PM
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Originally Posted by FBinNY View Post
Here's a trick that sometimes works, especially if the crank remover has somewhat sloppy threads.

What follows assumes that it's not something dumb like the plunger being too big for the square hole.

Thread the remover body to the bottom then back off 1/2 turn. Thread plunger in and tighten until it gets very hard to turn. Now get a decently heavy hammer, and deliver a solid blow to the back end of the pusher bolt. This can advance it within the slop in the threads, often breaks any bond holding the parts. Return to turning the bolt and see if it's now ready to come apart.

BTW- this shouldn't be used as SOP, and reserved for only those situations that call for it. I usually use it if someone shows me a crank remover that broke.

If that fails, the 100% never fails surefire method is with a pair of Jacobs chuck wedges. Chuck wedges have been my fallback for stripped cranks for over 40 years and have never let me down.
Thanks for the tips. How do you use the chuck wedges?

I can see it now. This goes from being a problem of getting a crank apart, to getting a Jacobs chuck apart.

Last edited by Gresp15C; 10-22-14 at 09:30 PM.
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Old 10-22-14, 09:32 PM
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Pickle fork, heat, and big hammer if all else fails.
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Old 10-22-14, 09:57 PM
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I've never been very happy with the removers that you grip with an adjustable wrench. My Park Tool has worked fine for 20 years. I would agree with FB's technique of threading the remover body all the way into the crankarm and then threading the plunger in until it contacts the crankarm. I would go to the next step of playing with the remover body and the plunger (they're different thread pitches) until there's a narrow angle between the crank arm and the remover handle. This allows you to squeeze the remover handle and crankarm together with both hands (and arms and shoulders if necessary).

It's tough to explain, easier to demonstrate. One of these days I'll make a video.
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Old 10-22-14, 10:25 PM
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Originally Posted by Jeff Wills View Post
I've never been very happy with the removers that you grip with an adjustable wrench. My Park Tool has worked fine for 20 years. I would agree with FB's technique of threading the remover body all the way into the crankarm and then threading the plunger in until it contacts the crankarm. I would go to the next step of playing with the remover body and the plunger (they're different thread pitches) until there's a narrow angle between the crank arm and the remover handle. This allows you to squeeze the remover handle and crankarm together with both hands (and arms and shoulders if necessary).

It's tough to explain, easier to demonstrate. One of these days I'll make a video.
Makes sense. It's how a differential micrometer works.
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Old 10-22-14, 10:43 PM
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Originally Posted by Gresp15C View Post
Thanks for the tips. How do you use the chuck wedges?

I can see it now. This goes from being a problem of getting a crank apart, to getting a Jacobs chuck apart.
Yes, they're essentially the same job.
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Old 10-23-14, 06:04 AM
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I have used plus gas with success.

Prior to my recent repaint, I couldn't get the right crank arm off. Tried the usual, crank puller, then a hub puller, plus gas etc.

Even loosened the bolt and rode around like that for weeks - nothing! (Problem was I carried the tools with me - if I hadn't you can bet it would have come off and left me stranded)

Eventually I used the plus gas again with the bike on it's side - crank bolt in and filled the crank end with plus gas. Left it a couple of days and off it popped.

John
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Old 10-23-14, 06:48 AM
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Kroil has been a better option than PB Blaster for stuck parts. Heat also works very well but not cooking hot.
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Old 10-23-14, 07:02 AM
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You did take the washer out of the crank arm before trying to remove it didn't you. Roger
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Old 10-23-14, 10:34 PM
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Originally Posted by rhenning View Post
You did take the washer out of the crank arm before trying to remove it didn't you?
I watched my boss do this on a nice old bike he was packaging for a friend. He forgot to remove the washer, so he stripped the threads on a Nuovo Record crank. Ooops...
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Old 10-24-14, 09:03 PM
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Thanks for the many nice tips. For now the crank has limbered up just from a couple of rides, so I'm leaning towards proceeding with caution to avoid wrecking anything. For this reason, I'll spray in some penetrating oil and just let it sit there for a week.
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Old 10-24-14, 09:08 PM
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Originally Posted by Gresp15C View Post
Thanks for the many nice tips. For now the crank has limbered up just from a couple of rides, so I'm leaning towards proceeding with caution to avoid wrecking anything. For this reason, I'll spray in some penetrating oil and just let it sit there for a week.
If you're riding locally, loosen the crank bolt 1/2 turn so the crank can pop free if it feels like it. Often super frozen cranks pop off when you climb a steep hill. Keeping the bolt in place will prevent any consequences, so don't remove it, just leave it 1/2 turn loose. If you're concerned about the bolt moving while it isn't tight, remove it and trap a length of dental floss in the spindle hole when you put it back. The floss will act like a Nylok and keep the loose bolt from migrating.
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