Impact drive to remove BB
07-10-17 | 09:29 AM
#1
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Joined: Jul 2006
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From: Middle of the road, NJ
Impact drive to remove BB
So I have a quest to remove a BB from a bike so I can replace the front derailer.(yeah, its a lower end kids size Giant). It's clear this bike has had a hard life, what ever can rust, has. The front derailer is frozen solid. The drive side BB cup it also pretty solid. Using a BB too, bolted to the axel, a long wrench, and wacking it hammer, didn't budge it. So I had the idea to put my 600ft\lb DeWalt impact driver on it to see if I can get it off. I know it's a cheap bike, and probably not worth the effort to get it off to replace it, but it's the principle and I DO NOT WANT TO BE DEFEATED! by this thing.
Has any body done this, and what was the result?
Like I said, it's a quest.
Has any body done this, and what was the result?
Like I said, it's a quest.
07-10-17 | 09:43 AM
#2
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Joined: Dec 2010
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From: northern Deep South
Bikes: Fuji Touring, Novara Randonee
The normal way to remove a frozen bottom bracket is to soak it (sometimes for weeks) with penetrating oil.
It's not clear to me why you need to remove the BB to replace the derailer; it'd probably be easier to soak the derailer mounting bolts with penetrating oil.
It's not clear to me why you need to remove the BB to replace the derailer; it'd probably be easier to soak the derailer mounting bolts with penetrating oil.
07-10-17 | 09:51 AM
#3
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Joined: Sep 2015
Posts: 1,689
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From: New Jersey
1) The manufacturer of the (bottom bracket) tool will not warranty it if you break it.
2) If you accidentally turn the impact driver the wrong way, you will likely destroy the tool/strip out the bottom bracket splines.
3) Trying to bust loose a stuck bottom bracket (especially if it is in an aluminum frame) has a good chance of toasting the threads in the frame. Use penetrant before attempting it, and realize that you'll likely need to chase the threads with a bottom bracket tap.
If you observe all the above, and are still okay with doing it, it can work just fine, though the tools themselves are not built for impact use.
For what it's worth, I found that an impact gun was a great expedient to working on bikes that lived hard lives, but it was rough on the tools. You risk damaging parts, especially if they are stuck, but for removing square taper cranks in good condition, a 'universal puller' with a long impact socket is the fastest. Use on expensive cranks at your own risk--I only used it to remove for disposal...
I maintained a 2 foot, 1/2" breaker bar for stubborn parts on a bike. If you wind up needing more than that, there's a good chance you'll damage something removing the part. A helper should hold down the bike on the ground (wheels on!), while you apply steady pressure. You may need a large socket to fit over the removal tool, especially for a bottom bracket; these are sold as impact sockets at auto parts stores, individually, for use on hub nuts. A 600 foot-pound gun simply may not have enough oomph for a stuck bottom bracket, given the size of the threading.
2) If you accidentally turn the impact driver the wrong way, you will likely destroy the tool/strip out the bottom bracket splines.
3) Trying to bust loose a stuck bottom bracket (especially if it is in an aluminum frame) has a good chance of toasting the threads in the frame. Use penetrant before attempting it, and realize that you'll likely need to chase the threads with a bottom bracket tap.
If you observe all the above, and are still okay with doing it, it can work just fine, though the tools themselves are not built for impact use.
For what it's worth, I found that an impact gun was a great expedient to working on bikes that lived hard lives, but it was rough on the tools. You risk damaging parts, especially if they are stuck, but for removing square taper cranks in good condition, a 'universal puller' with a long impact socket is the fastest. Use on expensive cranks at your own risk--I only used it to remove for disposal...
I maintained a 2 foot, 1/2" breaker bar for stubborn parts on a bike. If you wind up needing more than that, there's a good chance you'll damage something removing the part. A helper should hold down the bike on the ground (wheels on!), while you apply steady pressure. You may need a large socket to fit over the removal tool, especially for a bottom bracket; these are sold as impact sockets at auto parts stores, individually, for use on hub nuts. A 600 foot-pound gun simply may not have enough oomph for a stuck bottom bracket, given the size of the threading.
07-10-17 | 10:29 AM
#4
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Joined: Aug 2011
Posts: 22,676
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From: CID
Bikes: 1991 Bianchi Eros, 1964 Armstrong, 1988 Diamondback Ascent, 1988 Bianchi Premio, 1987 Bianchi Sport SX, 1980s Raleigh mixte (hers), All-City Space Horse (hers)
So I have a quest to remove a BB from a bike so I can replace the front derailer.(yeah, its a lower end kids size Giant). It's clear this bike has had a hard life, what ever can rust, has. The front derailer is frozen solid. The drive side BB cup it also pretty solid. Using a BB too, bolted to the axel, a long wrench, and wacking it hammer, didn't budge it. So I had the idea to put my 600ft\lb DeWalt impact driver on it to see if I can get it off. I know it's a cheap bike, and probably not worth the effort to get it off to replace it, but it's the principle and I DO NOT WANT TO BE DEFEATED! by this thing.
Has any body done this, and what was the result?
Like I said, it's a quest.
Has any body done this, and what was the result?
Like I said, it's a quest.
07-10-17 | 12:34 PM
#5
Thread Starter
Senior Member
Joined: Jul 2006
Posts: 3,135
Likes: 108
From: Middle of the road, NJ
If you observe all the above, and are still okay with doing it, it can work just fine, though the tools themselves are not built for impact use.
For what it's worth, I found that an impact gun was a great expedient to working on bikes that lived hard lives, but it was rough on the tools. You risk damaging parts, especially if they are stuck, but for removing square taper cranks in good condition, a 'universal puller' with a long impact socket is the fastest. Use on expensive cranks at your own risk--I only used it to remove for disposal...
For what it's worth, I found that an impact gun was a great expedient to working on bikes that lived hard lives, but it was rough on the tools. You risk damaging parts, especially if they are stuck, but for removing square taper cranks in good condition, a 'universal puller' with a long impact socket is the fastest. Use on expensive cranks at your own risk--I only used it to remove for disposal...
I maintained a 2 foot, 1/2" breaker bar for stubborn parts on a bike. If you wind up needing more than that, there's a good chance you'll damage something removing the part. A helper should hold down the bike on the ground (wheels on!), while you apply steady pressure. You may need a large socket to fit over the removal tool, especially for a bottom bracket; these are sold as impact sockets at auto parts stores, individually, for use on hub nuts. A 600 foot-pound gun simply may not have enough oomph for a stuck bottom bracket, given the size of the threading.
The most important thing is getting it off, if it does damage to the BB and the bike has to be scraped, no big deal. It will be scraped if I don't get it off anyway. The exercise is to find out how much force it takes.
07-10-17 | 12:37 PM
#6
Thread Starter
Senior Member
Joined: Jul 2006
Posts: 3,135
Likes: 108
From: Middle of the road, NJ
Shimano c101 type, it doesn't clamp on to the seat tube, but rather has a bracket that is attached to the BB.
07-11-17 | 04:01 PM
#7
Senior Member
Joined: Feb 2004
Posts: 30,225
Likes: 649
From: St Peters, Missouri
Bikes: Catrike 559 I own some others but they don't get ridden very much.
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