corbett79

I am restoring an old GT outpost. I am unable to remove the drive side crank arm bolt. I’ve already tried soaking in PB Blaster and using a bolt extrator socket since it had rounded edges. I was able to get the non-drive side off with no problems. The crankset is a Suntour XR 27. I am trying to replace the crankset, cassette, chain, etc. and not off to a good start. I’m thinking I may have to replace the bottom bracket now as well. Will I have to cut the crank off? Will this make it more difficult to remove the bottom bracket? Thanks for your help and suggestions.

Crankycrank

Don't give up yet. Try tightening the bolt slightly before attempting to loosen. Sometimes this is just enough to break the bond of a stuck bolt. Pour boiling water on the crank around the bolt area trying not to heat up the bolt itself before trying to loosen it. Give the bolt head a wack with a hammer and punch. Down the list a bit would be to drill the bolt head off and use your puller to get the crank off which will give you enough of the bolt to grab onto with some vise grips (it might come out easy as well with no tension on it from the crank) and you can save the BB and crank.

70sSanO

I would drill it out. Find a drill that is larger than the thread diameter but smaller that the square taper. Give yourself enough leeway if the drill is not perfectly centered.

The bolt head should come off or easily break off. You will still need a puller to remove the crank, but you will salvage it.

John

Jeff Neese

If you were going to change the crankset anyway, there's a good chance you'd need a different bottom bracket anyway. And for the price of a new bottom bracket, I'd consider that to be sacrificial if necessary. Can you get a good enough grip on the driveside cup without removing the crank, to be able to unscrew it and remove the whole thing crank and all?

SpedFast

Drill out the bolt and use an 'easy out' bit to extract it.
The heat from drilling into a hardened bolt will break the bond with the crank. Works everytime.

redshift1

Not sure how rounded off the crank bolt is but sometimes you can get a different size socket, perhaps even metric in place of imperial or v.v., usually requiring firm tapping on the socket to re-engage the bolt. If you can get some sort of purchase there, you would probably be amazed at how a "rattle" / impact gun can get these stuck fasteners loose. I'm guessing you don't have one but if you ever decide to purchase one, you no longer also need an air compressor as they now come in standalone electric versions.

You could also try "shocking the bolt " loose. This still requires a good purchase of the socket on the bolt and you do this by striking the socket handle with a steel hammer. In effect a manual version of the rattle gun. Best not to use a ratchet handle to avoid damaging the ratchet.

If your bolt head is too rounded for these things to be tried, and you really want to save your crankset, you will have to try removing the bolt head only. That's probably doable but is going to be hard due to limited access I would think. Things like grinding off the head or even drilling through the bolt head or milling the head off. But this sort of work requires a high level of know how ( and the equipment ) and if you are inexperienced, you may end up damaging the crankset and the axle.

corbett79

Thanks for the quick responses. I’d attach pictures, but it won’t let me until I’ve posted 10 times. 😆 Jeff Neese , where would I be looking to unscrew the cup? It would be ideal if I could remove the whole thing. Worse case, I’ll drill into that bolt and extract as suggested by a few. I’m not looking to save anything.

70sSanO

If it is a cartridge BB, you can’t wrench it out with the crank attached.

If it is a cup-cone, you might get a thin headset/BB wrench if you have chainring clearance.

John

Edit added: My Park HCW4 is closed end wrench is 36mm for the DS. My headset wrench (?) HCW5 is open end 32mm. I use the spanner end for the NDS.

corbett79

70sSanO it is a cartridge bottom bracket. 7 more posts and I can attach pictures. 😂 redshift1 I did try using an impact driver and striking the ratchet with a hammer.

dedhed

You can try pounding a SAE 6 point socket on a rounded metric.
Either way you should be using a 6 point if you're not.

Mr. 66

THe last time I had a stubborn crank bolt I used a cheater bar on the wrench and a j-clamp on the cranks to extend for greater torque

Jeff Neese

I just read that it's a cartridge, so that idea wouldn't work. A cup could be unscrewed with some sort of open-end wrench or maybe thin vise-grips. It might be tough grinding off the head or drilling it out - those bolts are pretty hard steel.

I'd be tempted to use a hacksaw and just cut through the axle. You realize a bottom bracket is cheap, right? Whatever method you use, don't worry about messing that up. Just don't damage the threads in the frame.

ClydeClydeson

It is possible a previous owner put some type of permanent thread locker on the crank bolt to stop it from unscrewing, which would indicate the square taper of the crank is rounded out and was causing the bolt to unscrew. If this is the case, the crank needs replacing (which I think you are doing anyways) so destructive removal of the crank from the spindle, and of the bolt from the spindle, would be appropriate. The solution would be to use a hacksaw to cut the crank away from the spindle, and possibly to cut the head off the bolt if necessary. Once the crank and bolt are removed you can access the BB cups with a spline tool to remove it from the frame and then install your new BB and crankset.

NB Loctite on the crank bolt is not the correct strategy for dealing with a self-loosening crank bolt, and his indicates a previous owner was not a competent bike tech, so I would consider every part of that bike suspect and not ride or sell without a complete tear-down and rebuild.

corbett79

out comes the dremel today! I’ll let you know how it turns out.

SurferRosa

"Don't give up. Don't ever give up."
- Jimmy V.

corbett79

nope, not today!

Jeff Neese

I'm curious to hear how the Dremel worked. I still think it would be easier to just cut through the axle, but that's pretty hard steel too. Some sort of carbide-tipped cutting wheel in a drill would work.

HillRider

A Dremel with an abrasive cut-off wheel will cut through practically anything. I've used them to cut short sections from Allen keys to make ratchet bits and allen keys are very hard. Use the fiber reenforced type of cut-off wheel as they are not likely to shatter, unlike the standard type.

BTW, and a little late to mention this, but you do realize both crank bolts are standard right-hand threaded, unlike English bottom brackets and pedal threads?

corbett79

Definitely too late now. So, to loosen/removal, you have to crank clockwise? The bolts were already rounded when I started, and the extraction sockets only seemed to work counterclockwise. I did try both directions.

I will look into the fiber reinforced wheel…I’m going through the standard ones quickly.

corbett79

Definitely too late now. So, to loosen/removal, you have to crank clockwise? The bolts were already rounded when I started, and the extraction sockets only seemed to work counterclockwise. I did try both directions.

I will look into the fiber reinforced wheel…I’m going through the standard ones quickly.

Crankycrank

No, no, no. Bolt is standard counter clockwise to loosen. I still think drilling off the bolt head is your best option first as you won't be doing any damage to the crank and probably easier.

Mad Honk 

So I am guessing that bolt extracting sockets like those from Irwin offer. One of those and an impact wrench should remove it. Heat will break down any lock-tite that might have been used. Just my thoughts. Smiles, MH

corbett79

I finally got the old crank off. I had to resort to an angle grinder. I am now struggling to get the old bottom bracket off. I’ve sprayed some PB blaster and WD 40 and plan to let it soak. I would upload a picture but I’m not yet at 10 posts.

biker128pedal

WD40 is useless. Mix a 50:50 solution of transmission fluid (red type) and acetone. There is also Aerokroil. Between these two and PB Blaster there are argument are the best. PB BLaster used to be good but it was made safer. Also after soaking it I've clamp the tool in a vise and rotated the frame to remove the locking cup on a cartridge BB before. More leverage.


https://www.kroil.com/?utm_term=aero...hoCHWEQAvD_BwE

corbett79

Thanks for the info