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Motobecane Bottom Bracket removal

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Motobecane Bottom Bracket removal

Old 05-01-12, 08:49 AM
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Motobecane Bottom Bracket removal


I have a rubbish bottom bracket on a rusty 1980 Motobecane frame that I fell in love with. I would really like it replaced, but it feels really stuck. By reading around on this forum, the suggestions are that it is a swiss BB, thereby clockwise on the right side to loosen. See linked image. Should I just put a big wrench on the 8-flats and turn by force?

Motobecane Bottom Bracket

Also a friend said that it would be possible to jam in a normal English threaded BB, is that right? Or do I have to give up this project?

Thank you for listening.
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Old 05-01-12, 09:18 AM
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If it is rusted on there use penetrating oil (PB, WD-40, etc..) and let it soak for a while. Then try to remove it.

If it is Swiss threaded you can have the BB retapped for English 68.

Worse case scenario is that you drill the BB out.
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Old 05-01-12, 09:26 AM
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If it is not swiss LH thd, then its French lefty loosie RH thread.

BD new faux Motobecanes are China export. so British thread ..
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Old 05-01-12, 11:39 AM
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50/50 auto tranny fluid / acetone is meant to be a great penetrant.

After soaking it in whatever, I'd give it a lot of taps with a hammer, maybe tape some cardboard around the stays, and bung it in a vice, with those big inviting flats.
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Old 05-01-12, 02:53 PM
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Your image appears to be the non-drive side, so you'd turn counter-clockwise to loosen that side. If the frame is in fact Swiss thread (1980 production date makes this possible), then the fixed cup on the drive side would loosen clockwise.

An English thread bottom bracket will not work for you. If the cups are unusable, a threadless cartridge bottom bracket such as that from Velo-Orange and other vendors ought to work.
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Old 05-01-12, 03:10 PM
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Agreed that an English BB threading will not work if the BB is either French or Swiss and damaged but it can be tapped out to Italian. I have done that before and it works well. I had a 531 Cilo with a Swiss BB that another mechanic ruined by trying to force in an English BB; I had it reamed out to Italian.
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