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-   -   Cranks stuck on square taper BB (https://www.bikeforums.net/bicycle-mechanics/1150284-cranks-stuck-square-taper-bb.html)

speedevil 07-20-18 07:05 AM

Cranks stuck on square taper BB
 
I have a set of Shimano 600 tri-color cranks that seem to be welded to the square taper BB. My park tool crank remover has not made any headway at all, and I'm reluctant to use any more torque on it for fear of stripping the removal threads. I have an automotive-type pulley/gear puller but the "hooks" are too large to fit between the back of the crank and the BB. I could grind them down, but is there a puller that others have used to remove stuck cranks? I'm willing to buy a tool if it will do that job properly without damage to the cranks.

Looking for recommendations. Thanks in advance.

Apparently I can't spell "square" this morning. Don't know how to edit the thread title.

FBOATSB 07-20-18 07:13 AM

One thing to try is to loosen the crank bolts a little, apply some penetrant, and ride up and down the street within walking distance. Unless working with an already bare frame.

exmechanic89 07-20-18 07:15 AM

I've never had a standard crank arm puller fail to remove the crank arm, even if it felt really tight on the spindle. I'd screw the puller in tightly and try again, it should remove the arm. If the threads do get pulled out instead of the arm coming off, you could also cut the crank arm off at that point, which of course will destroy the arm.

speedevil 07-20-18 07:16 AM

[MENTION=380471]FBOATSB[/MENTION], that ship already sailed. The only components on the frame are the cranks/BB. For what it's worth, the crank bolts backed out fine and both were greased.

Steve B. 07-20-18 07:16 AM

Wood dowel and/or narrow stick, knock away at it from non- drive side with a mallet ?

FBOATSB 07-20-18 07:17 AM

Mods are feverishly back pedaling the BF machinery to fix that typo as we speak:)

2cam16 07-20-18 07:53 AM

Try applying some heat on it too. This has worked for me a couple of times with a heat gun.

mrv 07-20-18 08:03 AM

i had to hack saw off a non-drive side crank. I think I somehow buggard things up with the proper crank removal tool - or more likely I had the wrong head size on the crank removal tool.

I think I might have tried one of these: https://www.autozone.com/loan-a-tool...80720135940:s#
But I don't see in the picture what goes on the "back side" of the crank. I will check when I get home if I don't see a post saying you have resolved your issue.

Dan Burkhart 07-20-18 08:28 AM


Originally Posted by speedevil (Post 20458936)
I have a set of Shimano 600 tri-color cranks that seem to be welded to the square taper BB. My park tool crank remover has not made any headway at all, and I'm reluctant to use any more torque on it for fear of stripping the removal threads. I have an automotive-type pulley/gear puller but the "hooks" are too large to fit between the back of the crank and the BB. I could grind them down, but is there a puller that others have used to remove stuck cranks? I'm willing to buy a tool if it will do that job properly without damage to the cranks.

Looking for recommendations. Thanks in advance.

Apparently I can't spell "square" this morning. Don't know how to edit the thread title.

Just double check that your crank puller isn't pushing against a washer instead of the spindle.

leob1 07-20-18 09:13 AM

Firstly, remove your puller, clean the threads on the crank, (check for a washer), screw the puller all the way in, use a wrench to make sure it's all the way in. Then proceed to remove the crank as your normally would. When you get as far as you can by hand, hit the puller handle or wrench with a dead blow hammer. Start soft, then harder until the crankk comes off.

Good Luck

dsbrantjr 07-20-18 09:51 AM


Originally Posted by leob1 (Post 20459206)
Firstly, remove your puller, clean the threads on the crank, (check for a washer), screw the puller all the way in, use a wrench to make sure it's all the way in. Then proceed to remove the crank as your normally would. When you get as far as you can by hand, hit the puller handle or wrench with a dead blow hammer. Start soft, then harder until the crankk comes off.

Good Luck

Another tactic to try is to get the puller as tight as you can by hand and then solidly strike the drive end of the puller with a 4lb hand sledge. The shock will often pop the crankarm loose. Extra points for applying Kano Kroil or PB Blaster (and waiting for it to creep into the joint) beforehand.

speedevil 07-20-18 10:28 AM

They're off. Both of them. It was a combination of PB Blaster, heat, and some hammering of the puller with an old hammer handle that did it. Wow! Those cranks were not coming off without some serious torque. Don't know what torque was used to tighten the crank bolts, but I'm guessing it was a lot higher than the spec calls for. Probably some "mechanic" tightening them by "feel" instead of using a torque wrench.

Thanks to everyone for the suggestions. Hopefully the BB won't be quite so hard to remove. A Campy BB for a Comp triple crank is going in it's place - once the frame is back from some paintwork.

toast3d 07-21-18 10:08 AM

I was going to suggest using a cheater bar for additional leverage. Glad to see you got the crank arms off.

Aubergine 07-21-18 10:50 AM


Originally Posted by speedevil (Post 20459385)
They're off. Both of them. It was a combination of PB Blaster, heat, and some hammering of the puller with an old hammer handle that did it. Wow! Those cranks were not coming off without some serious torque. Don't know what torque was used to tighten the crank bolts, but I'm guessing it was a lot higher than the spec calls for. Probably some "mechanic" tightening them by "feel" instead of using a torque wrench.

Not necessarily. Sometimes things just get corroded together, especially if they have not been disturbed for a long long time.

Jeff Wills 07-21-18 10:11 PM


Originally Posted by speedevil (Post 20459385)
They're off. Both of them. It was a combination of PB Blaster, heat, and some hammering of the puller with an old hammer handle that did it. Wow! Those cranks were not coming off without some serious torque. Don't know what torque was used to tighten the crank bolts, but I'm guessing it was a lot higher than the spec calls for. Probably some "mechanic" tightening them by "feel" instead of using a torque wrench.

Maybe not- if they were installed 30 years ago with the tapers cleaned of any grease at the specified 300 to 400 inch-pounds of torque... they won't come off without a bunch of force. I've resorted to hammering on the handle of the crank puller a few times.

desconhecido 07-21-18 11:09 PM

I've only experienced this once and that was with a Miyata 1000 that I bought a couple months back. I'm pretty sure that nothing had been done to the Miyata since new as it still had the original tires and the original sponge on the bars, etc. The crank was tight on both sides, but a couple whacks (and who wouldn't want to whack a crank?) with a light hammer on the old Park crank tool and they were free, free, free at last.

speedevil 07-22-18 08:19 AM

There was very little corrosion evident once the cranks were off, and the tapers were covered in PB Blaster so I couldn't tell if they were assembled dry or not. On the positive, they weren't going to come loose without something dramatic happening. I guess you'd have to say that the install was properly done from that perspective. Once the TdF stage is complete, I'll take the BB out and get the frame/fork cleaned up and ready for paint.

I ordered some white paint markers for the Pinarello (Uni Posca extra-fine) but they're coming from Japan, so won't have them for a little while. Hopefully they will work well for the panto on the Pinarello. I need to service the hubs, install pedals, and set up the cockpit - then the Pinarello will be ready for a maiden voyage.


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