Severely seized square-taper crank
#1
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From: England, currently dividing my time between university in Guildford and home just outside Reading
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Severely seized square-taper crank
I'm building up an old frame as a singlespeed, and I've got a junk bike with an old Sugino crankset I want to use. The only problem is that the right-hand crank is completely seized onto the bottom bracket spindle. I've torqued the heck out of a crank puller on it, and I'm sure the puller is pushing the end of the spindle not on some kind of washer in the crank, but it won't budge. The left-hand crank came off pretty easily, but I'm at my wits' end with the right-hand one. I could work out some way to torque the crank puller harder, but I'm worried I'll strip the puller threads out of the crank. Any suggestions? Penetrating spray? Heat?
#2
Senior Member
Joined: Jan 2012
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From: Spokane, WA
Bikes: Specialized Sequoia Elite/Motobecane Fantom Cross Team Ti/'85 Trek 520
How hard is hard? I have had to put a cheater pipe on one crank that was really stuck on there. I was very worried I was going to strip it but it didn't strip. At that point, if it started to strip, I was going to put a ball joint fork inbetwen the crank and the BB and give it a couple of good smacks with a steel hammer while the crank puller was still on there.
I didn't have to resort to that though, the crank arm finally popped off.
I didn't have to resort to that though, the crank arm finally popped off.
#3
Cottered Crank
Joined: Aug 2010
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From: Chicago
Bikes: 1954 Raleigh Sports 1974 Raleigh Competition 1969 Raleigh Twenty 1964 Raleigh LTD-3
If you are SURE there isn't a washer in there (you looked inside and can plainly see the square-taper BB end inside without anything in the way) then it should come off.
Check to be sure you have the right crank remover or that it is set up correctly and you don't have the wrong end-piece on. Some crank pullers have two different removable ends that pivot. If you have the bigger end (used for ISIS or Octolink cranks) on the crank puller it isn't going to be pressing on the BB and instead on the inside of the crank arm -just like if you had a washer in there. The end of the crank puller should have a pushing-end that is no larger than the diameter of the BB spindle. Make sure you didn't break something off or leave a piece behind in the other crank when you took it off.
Also, lubricating the threads within your crank-puller tool helps a lot too by reducing the internal friction. Regular grease works very well here. Lubing the threads of this type of tool is a regular maintenance chore that should be performed every once in a while to ensure they don't bind up.
If everything is lining up and fitting correctly and you have so much tension on the puller threads that you are afraid your are going to strip them then a give the crank a few bops with a big rubber mallet. You aren't trying to "hit" the crank off but simply add in some high-frequency vibrations into the joint while the tool is loading the pieces with pressure. A light and steady tap-tap-tap will get the metal vibrating and this sometimes help get things moving. You can also help things along by spraying in some high-quality penetrating oil designed for seized things like this. There is a product called "freeze-off" that works pretty well in these types of situations.
Check to be sure you have the right crank remover or that it is set up correctly and you don't have the wrong end-piece on. Some crank pullers have two different removable ends that pivot. If you have the bigger end (used for ISIS or Octolink cranks) on the crank puller it isn't going to be pressing on the BB and instead on the inside of the crank arm -just like if you had a washer in there. The end of the crank puller should have a pushing-end that is no larger than the diameter of the BB spindle. Make sure you didn't break something off or leave a piece behind in the other crank when you took it off.
Also, lubricating the threads within your crank-puller tool helps a lot too by reducing the internal friction. Regular grease works very well here. Lubing the threads of this type of tool is a regular maintenance chore that should be performed every once in a while to ensure they don't bind up.
If everything is lining up and fitting correctly and you have so much tension on the puller threads that you are afraid your are going to strip them then a give the crank a few bops with a big rubber mallet. You aren't trying to "hit" the crank off but simply add in some high-frequency vibrations into the joint while the tool is loading the pieces with pressure. A light and steady tap-tap-tap will get the metal vibrating and this sometimes help get things moving. You can also help things along by spraying in some high-quality penetrating oil designed for seized things like this. There is a product called "freeze-off" that works pretty well in these types of situations.
#4
Senior Member
Joined: Apr 2006
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You can carefully apply heat with a propane torch to the crank at the bb spindle. The crank arm is aluminum and the spindle is steel. Aluminum will expand faster than steel and the crank arm will loosen up. There is a risk that the threads where the puller is engaged will also expand and this could cause the puller to strip the threads. Also you will have to be careful not to let the torch melt any plastic and such that might be in the area.
#5
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From: Mid Willamette Valley, Orygun
Bikes: 87 RockHopper,2008 Specialized Globe. Both upgraded to 9 speeds. 2019 Giant Explore E+3
Lay the bike on its left side and fill the spindle cavity with penetrating oil. (the real stuff, not WD-40)
Let it sit a couple hours.
Tap lightly with a wrench to "vibrate" things every 15-30 minutes while sitting.
The crank should "jump off"!
Let it sit a couple hours.
Tap lightly with a wrench to "vibrate" things every 15-30 minutes while sitting.
The crank should "jump off"!
#6
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From: Mesa, AZ
Bikes: Moots RCS, tandem, beach-cruiser, MTB, Specialized-Allez road-bike, custom track-bike
In cases like these, I use a motorcycle tyre-iron. Wedge it in between the crankarm & fixed-cup with the tip of the iron aimed at the crankarm. Pry towards the seat-tube and >POP< off it goes in 2-3 seconds.
Of course, depends upon how much exposed spindle you have between the crankarm & fixed-cup. With larger clearances, I've used a pickle-fork, used to separate automotive A-arms from ball-joints. Both methods causes minimal damage to crankarm and it can be re-used if you want.
Of course, depends upon how much exposed spindle you have between the crankarm & fixed-cup. With larger clearances, I've used a pickle-fork, used to separate automotive A-arms from ball-joints. Both methods causes minimal damage to crankarm and it can be re-used if you want.
#7
Buy a set of Jacobs Chuck removal wedges($10), use it like DannoXYZ suggests for the tire-iron " Wedge it in between the crankarm & fixed-cup". Works great, no damage. BTW, WD-40 is one of the least effective penetrating fluids, it is more of a water dispersing agent. PB blaster is much better, and the best is a home brew of 50% acetone and 50% transmission fluid.
Brian
Brian
#8
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From: Spokane, WA
Bikes: Schwinn Peloton Ventana El Saltamontes Spec Stumpjumper Conversion Gravel
Buy a set of Jacobs Chuck removal wedges($10), use it like DannoXYZ suggests for the tire-iron " Wedge it in between the crankarm & fixed-cup". Works great, no damage. BTW, WD-40 is one of the least effective penetrating fluids, it is more of a water dispersing agent. PB blaster is much better, and the best is a home brew of 50% acetone and 50% transmission fluid.
Brian
Brian
#9
Senior Member


Joined: Dec 2007
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From: San Jose, California
Bikes: 2001 Tommasini Sintesi w/ Campagnolo Daytona 10 Speed
Before you go to the extremes, visit an LBS that has a bonafide version of the Campagnolo crank extractor - with the floating press head. Try that first.
Not all tools are the same...I can stick a Park in, no luck, stick in the same design from Campy - off it comes.
=8-)
Not all tools are the same...I can stick a Park in, no luck, stick in the same design from Campy - off it comes.
=8-)
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5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
#10
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From: Minneapolis, MN
Bikes: '86 Trek Elance 400; '83 Trek 520; 90s Specialized Crossroads, '84 Trek 610 (wife's), 90s Trek Multitrack (wife's), Cargo Trailers, Burley for the Kids, WeeHoo Trailer
I had this happen once. I used a pickle fork (looks like a large tuning fork the tapers out) that I picked up from Napa (for about $8) to remove the crank. I just used the fork and worked my way around the crank (putting the fork between the bottom bracket and crank) and kept hitting it with a hammer until it popped up. It still took awhile and a lot of force to get that crank off. I would try the penetrating oil first as the pickle fork option seemed to be a little harsh. When I did it, I didn't end up marring the crank (or bb) - but, it still seemed a bit like a severe operation.
#11
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#12
If the bike is rideable - take it outside and go ride in circles.
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72 Frejus (for sale), Holdsworth Record (for sale), special CNC & Gitane Interclub / 74 Italvega NR (for sale) / c80 French / 82 Raleigh Intl MkII f&f (for sale)/ 83 Trek 620 (for sale)/ 84 Bruce Gordon Chinook (for sale)/ 85 Ron Cooper / 87 Centurion IM MV (for sale) / 03 Casati Dardo / 08 BF IRO / 09 Dogma FPX / 09 Giant TCX0 / 10 Vassago Fisticuff
#13
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From: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
As an alternative, you can use a pair of Jacobs chuck removal wedges behind the crank to push, rather than pull it off the spindle. The wedges are fairly cheap (about $10.00 or less) and 100% successful for this job.
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An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
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