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Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

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Old 09-27-04, 10:02 PM   #1
Balance
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tricks for removing stuck bb?

So, it's time to change the pastey bb on my mtb, but we can't get the darned thing out. Went so far as to put the whole bike up in a vice, squeezing the bb remover and trying to turn the bike. No good. I've heard that some people heat the bb shell to get accomplish this, but wouldn't that melt the paint? Also, I'm thinking i want to replace it with an oldschool non sealed bb because it would be a lot cheaper (free used parts) and much easier to service. I don't mind working on my bike, so the seals are just something to damage. But I'm not sure if I can install that type of bb. It would likely be a road bb, and because my mtb is a bit older, the bb shell isn't overly oversized. Has anyone done this before?
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Old 09-27-04, 11:23 PM   #2
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You need to apply a specific freeing up agent to the BB threads for a few days to let it soak in. In the UK, we have a product called Plusgas that comes in a spray or a drip can that works pretty well. If your frame is bare metal or baked enamel, heating the BB shell with a hair dryer could help unseize it; I wouldn't use a hot air gun as they're probably too hot. HTH .
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Old 09-28-04, 01:15 AM   #3
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Bike frame presumed to be steel, but doesn't really matter. Check the bottom (road) side of the BB
shell for a hole. Sometimes, in older frames for drainage or newer frames tapped holes to fasten the
cable guide holes are there. If so this gives a way to squirt/inject/dribble the thread loosener of
choice in and to let it work as Balance suggests, with the frame on its side to let the fluid percolate
into the threads. Enormous torque can be put on the fixed cup on the R hand side by clamping the
cup in a sharp topped jaw vise and using the frame as a wrench. It is important that the frame
be rotated in the correct direction. See discussion on this by Sheldon at www.sheldonbrown.com
look for Bottom Bracket adjustments. If there is no hole in the bottom of the BB shell don't feel
shy about making one. Get a 0.125" or so drill and have at it, but don't push real hard. Use a bit
of rubber and a short self tapping screw to seal the hole afterwards. There is always the LBS.
Steve
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Old 09-28-04, 08:36 AM   #4
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If you want to get it out fast, the only thing to use is an impact driver, though I would use a light duty one to start out adjusted to its lowest setting and work up from there. I have to admit, I've never heard of anyone using one on a bike but they are truly amazing on all other applications I have ever seen.
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Old 09-28-04, 09:15 AM   #5
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Quote:
Originally Posted by Walipala
If you want to get it out fast, the only thing to use is an impact driver, though I would use a light duty one to start out adjusted to its lowest setting and work up from there. I have to admit, I've never heard of anyone using one on a bike but they are truly amazing on all other applications I have ever seen.
Yep, I was going to suggest this. I have a manual handheld one (you hit it w/ a hammer) made by Craftsman. Used it recently to get a stuck BB off.
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Old 09-28-04, 10:25 AM   #6
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Before you get carried away with using major force on your bottom bracket, make sure that you're going the right way. The most common bicycle bottom brackets are English threaded which means that the right (drive) side has a left hand thread so you turn it clockwise to loosen.
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Old 09-28-04, 02:30 PM   #7
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Are you doing this yourself? I let my LBS remove the fixed cup of old style cup and cone bottom brackets because they have the proper tool for removal. The tool grips the bb firmly. These things are REALLY tight and, assuming non-Italian, are reverse threaded. I don't think it is worth risking damage to the frame to try it myself even though I feel comfortable with everything else.
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Old 09-28-04, 08:36 PM   #8
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You always remove the left (non drive) side first in a counter clockwise direction. Then the right (drive) side clockwise. You may have to apply Liquid Wrench or any other penatrating oil, to the threads over night. I found using an adjustable wrench and a cheater bar very helpful.
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Old 09-28-04, 08:49 PM   #9
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This was attempted in a fully equiped repair co-op, so all the tools are there. The bb tool that works with my bb doesn't fit perfectly, so it's a balancing act with the hole bike up in the vice, using the frame as a wrench. One person balances, one person turns the frame. I didn't want to strip it, so stopped before we got really gung-ho. There's no holes in the bb shell. We did use liquid wrench, but didn't let it sit overnight, just for half an hour. I didn't realize that a simple hairdrier would help. So here's my plan for the second attempt. Apply liquid wrench, wait a whole night. Return the next day, do the same as before with the bike up on the vice and try to loosen. If it doesn't work, apply heat from the hairdrier. How long are supposed to heat it for? Oh yeah, and it's 4130 steel. If this doesn't work, attempt to remove the fixed cup. By the way, what's an impact driver? I've certainly used hammers and mallets, and chisels and stuff, but an impact driver?

thanks for all the tips!
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