Removing a Stuck Bottom Bracket

PB Forum :: Mechanics' Lounge
Removing a Stuck Bottom Bracket
Previous Page |
Author Message
Posted: May 7, 2008 at 8:58 Quote
Hi,
I've been trying to remove my old bottom bracket because I got a new XT crankset that I want to install. It's an entry level, square-tapered, fairly standard bottom bracket that came with my bike. It uses this type of tool to remove it:
http://www.chainreactioncycles.com/Images/Models/Full/680.jpg

The problem is that it's been in the bike for four years. It is completely stuck, I can't get it to move at all. I tried clamping the wrench which is plugged into the tool to the bottom bracket with a vice grip, then pushing down on the wrench (8" long) with all my strength, but it does not show any signs of loosening.

I have tried:
-squirting some solvent on it
-hitting it with a hammer
-warming it up with a blowtorch then pouring water over it repeatedly to get it to expand, then contract

Are any of these techniques useful? If not, are any of them harmful so that I make sure not to try them again? What do you recommend to do here? I would like to do this myself, but if necessary I will go to the bike shop to get it done once I've exhausted any possibilities. I have no problem with destroying the bottom bracket in the process, but want to keep the frame intact.

I did a search about this, but did not find anything that was truly relevant, by the way.

Thanks!

Posted: May 7, 2008 at 9:08 Quote
well you could try sliding a longer bar over the wrench or ratchet for more leverage or let the bb and frame to soak in penetrating grease overight then try..

Posted: May 7, 2008 at 9:10 Quote
yah wat he said. or get a friend to help u

Posted: May 7, 2008 at 9:11 Quote
put bb tool in vice and use position bb in tool. whilst pushing down on area around bb turn the frame [make sure its the right way] this way you'll have far more leverage than a ratchet or allen key

Posted: May 7, 2008 at 9:13 Quote
armydave wrote:
put bb tool in vice and use position bb in tool. whilst pushing down on area around bb turn the frame [make sure its the right way] this way you'll have far more leverage than a ratchet or allen key
yea thats what i was thinking

Posted: May 7, 2008 at 11:06 Quote
Buy or make one of these:
http://www.pedroscatalog.com/images/560/6460210.jpg
Out of a longer bolt and some washers. I cinches the BB tool onto the cup.

Try dripping the penetrating oil down the seat tube if your BB shell will allow it so you can get the action going on the inside threads.
Also, make sure you're taking out the non-drive side first (counterclockwise), then drive side (clockwise) to loosen them.
Good luck.

Posted: May 7, 2008 at 12:39 Quote
I already tried with a friend, and it didn't work. I don't think I can try turning the bike rather than the tool, seeing as the only vice grips I have are the portable kind, not one that are mounted onto workshop tables.

I maybe should give a go with more leverage, if I find a pipe that I can slide over the wrench I will do that. I would be happily surprised if it works though, it seems really stuck.

I hadn't heard about this penetrating grease. Can I buy it at a bike store, a hardware store...? As far as pouring it down the seat tube goes, should I just look down into the tube with a flashlight and see if it opens up to the bottom bracket shell? If I just leave the bottom bracket and the frame to soak, will it be able to get in if I leave it for a while? Should this be effective?

The direction I checked many, many times, so I haven't been accidentally tightening it. I have been working on the non-drive side as well.

BMW, I am not fully sure that I understand that tool, but I have an idea: the bolt goes through the BB tool, threads into the bottom bracket spindle like would a crank bolt, then I clamp it down with the threaded washer (all this at the bottom end in your picture). What I don't get is how the top part works. What is it for, and how do I get a tool wrench onto the whole mechanism with which to turn the BB tool?

I came up with a sketchy and quite destructive method which I should probably only use as a last resort, if at all: I saw off the parts of the spindle that stick out. Then, I drill the bottom bracket through and through, so that I can fit a small saw or file through , then kind of cut up the bottom bracket so I can take out pieces, and not have to unscrew it. Is this feasible, or just plain stupid?

Thanks!

Posted: May 7, 2008 at 12:46 Quote
When you heat something up with a torch, you should never throw water on it. It can crack the steel and then you need a whole new frame. Lots of penetrating lubricant (PB Blaster is great, as is Aerokroil), maybe a cheater bar on the ratchet you're using, and it should come out. Let the penetrating oil sit for at LEAST 24 hours, keep replenishing it as necessary every day or so that you let it sit. If it still doesn't come loose, then you can start heating up the frame with a torch. Do not hit the BB itself, as that is what you want to keep small, but you want the frame to expand enough to loosen itself from the BB. Do not stay in one spot too long either or you'll burn your paint off. Keep moving the torch, and possibly tap the frame with a soft-faced hammer (rubber or plastic) to break the adhesion. Keep at it and it'll come eventually.

P.S. Your super-destructive method will probably ruin something else in the process, I would NOT do it until you've spent at least a week trying my way.

Posted: May 7, 2008 at 12:53 Quote
Well, my frame is aluminum...does pouring water have the same effect? I hope I didn't cause much damage, but I didn't reach a very high heat with the blowtorch anyway...

I will try to get my hands on some penetrating lubricant/grease as soon as possible and have my bottom bracket soaking in it.

About the heating up - I feel stupid, but I was doing the exact opposite from what I should of...that's what I am studying in physics right now too, I really didn't give that enough thought. I will keep that in mind if I need to heat it again.

Thanks for the advice!

Posted: May 7, 2008 at 13:01 Quote
silaslecake wrote:
Well, my frame is aluminum...does pouring water have the same effect? I hope I didn't cause much damage, but I didn't reach a very high heat with the blowtorch anyway...

I will try to get my hands on some penetrating lubricant/grease as soon as possible and have my bottom bracket soaking in it.

About the heating up - I feel stupid, but I was doing the exact opposite from what I should of...that's what I am studying in physics right now too, I really didn't give that enough thought. I will keep that in mind if I need to heat it again.

Thanks for the advice!

Aluminum will crack as well, so you gotta be real careful with it.

It has to be a penetrating OIL, grease won't penetrate anywhere.

Common n00b mistake about the heating up. I've worked as a snowmobile/atv/motorcycle mechanic for the past 5 years so I know all about rusted/stuck bolts and parts.

Good luck!

Posted: May 8, 2008 at 23:07 Quote
you know, its proly reverse thread.... you proly allready know this but i dont think anyone else has said it.

to summerize, drive side reverse thread(turn clockwise to loosen). left side normal thread(turn counter clockwise to loosen)

Posted: May 8, 2008 at 23:11 Quote
It shouldn't be this hard. It could be Italian threads. What frame is it?

Posted: May 8, 2008 at 23:36 Quote
Steel cups + aluminum frame - grease +time = hellishly stuck BB.

We've seen cups that literally tore the threads out before the cup would unthread in the shell. It's just going to take an amazing amount of torque and penetrating oil to make it happen.

Posted: May 9, 2008 at 9:05 Quote
brooklynmachine wrote:
Steel cups + aluminum frame - grease +time = hellishly stuck BB.

Yep, lack of grease = direct aluminum to steel contact = chemical reaction = oxidation out the ass. Gotta brush the threads with anti-seize compound before you put it in next time!

Posted: May 9, 2008 at 12:22 Quote
Yay! That bottom bracket got pwn3d.

I went out and bought some penetrating oil yesterday and let my bottom bracket soak in it all night. Today I found another clamp in my basement and found a good angle to really solidly hold the bottom bracket in tool. I slipped an old handlebar I had over my wrench (60cm is better than 20cm) and pushed. It gave away so easily! Then the other side came off just as easy. Hooray.

By the way, I just installed my XT crankset, and did put some grease on the threads, but no "anti-seize" compound. I had a feeling that the threads of the bottom bracket cups came with the anti-seize compound: they had a sort of thick white substance on them. Is this the case? (or is that lock-tite? :S) I don't want my bottom bracket to seize up again!

Thanks for your help!

Previous Page |

 
Your subscriptions
no posts

Copyright © 2000 - 2014. Pinkbike.com. All rights reserved.
dv16 0.029734
Mobile Version of Website