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Can't remove BB!(3 posts)

Can't remove BB!Velocipedio
Jul 27, 2002 3:54 PM
I'm rebuilding my 'cross bike with Campy Centaur components. I've stripped everything, but I can't seem to get the bottom bracket to budge. It's a Shimano UN52, and when I tried to loosen the drive side BB cup [English thread, loosen clockwise], it just doesn't move. How stuck is it? I tried with the torque wrench and I torque a whole lot higher than the 70nM it was supposed to be tightened to. I tried pouring hot water over the BB shell -- nothing... I don't want to force it or break anything, but I'm at wit's end here. This should not be this difficult. In fact, the left cup comes off pretty easily.

Any ideas? I'll even accept ideas that result in the destruction of the BB; I was planning to use it on another bike, but I'd be happy to get another, if necessary.

One more thing... am I right that the cups on the BB-UN52 are plastic?
Couple of ideasSpoke Wrench
Jul 27, 2002 6:30 PM
1. Check the archives. There have been some ideas posted that I havn't tried. This topic comes up regularly.
2. Try a genuine Shimano bottom bracket tool. The Shimano tool sits closer and flatter to the bottom bracket and makes it easier to apply big torque.
3. Remember spin-on freewheels? I've used the same trick with bottom brackets. Chuck your bottom bracket tool in the bench vise, have a helper assist you in threading the bottom bracket onto the tool and spin the whole bike anti-clockwise.

Shimano cartridge bottom brackets are really just anchored on the drive side. The nylon thingie on the left that you removed is just a spacer to keep the cartridge from tipping when you pur force on the pedals. It isn't really a bearing cup.
You know it's left hand thread, right? (nm)Kerry
Jul 28, 2002 5:02 PM