Removing a stuck Mavic 610 unthreaded bottom bracket...any ideas?

[jim haseltine]

If anything gets through the corrosion it'll be Bilt Hamber Deox-C. It might take a few days but I've know it wick it's way under powder coat. The problem would be finding some sort of container of a suitable size and shape that wouldn't mean using several gallons of the stuff just to be able to submerge the entire BB shell. However, I suspect you'll end up taking the advice to chop it to bits.

 

[bikeworkshop]

Let's not forget the caustic option.

 

[FZRIP]

Recent caustic success…

 

[sjcprojects]

Yes, caustic is always an option. Once the axle and bearings are removed it will just be the BB body stuck in there, which one way or another can be gotten out. I would prefer to save the BB, but realistically that's probably not really an option.

I had naively thought that being unthreaded, it might actually come out okay, but this bike was obviously sat outside (or at least somewhere very damp) for a pretty long time in the past, and water has clearly done its damage. Somewhat ironically the BB itself actually feels perfectly fine, so it's clearly very well sealed (I've read these do have a reputation for lasting a long time).

Anyway, this is a longer term project, so I may not get around to doing it for a little while. I'll update when I do manage to make any progress, just in case anyone else has the same issue in the future.

 

[non-fixie]

Let's not forget the caustic option.

+1. Cheap, easy and - most importantly - a very clean result with no damage to the threads.

Stuck bar stem in a Raleigh steerer:

Hanging in a drain cleaner solution (sodium hydroxide) for a couple of hours:

The end result:

 

[chickendrumsticks]

Will caustic soda have the same effect on what is clearly extensive iron oxidation I. E. rust as it does on alloy?

 

[bikeworkshop]

Just a note to anyone considering using Caustic soda:

It attacks organic matter, that includes you, your friends, family, passers by, pets.


If you mix it up too strong, it can boil, spit and froth.

I don't do it at work because it is too hard to isolate from human contact.

 

[bikeworkshop]

Caustic dissolves aluminium. Iron alloys and oxides are unaffected.

Some people attempt to dissolve the oxides (ammonia, prussic acid iirc) but if the bond layer is compressed, penetration is difficult.

 

[non-fixie]

Just a note to anyone considering using Caustic soda:

It attacks organic matter, that includes you, your friends, family, passers by, pets.


If you mix it up too strong, it can boil, spit and froth.

I don't do it at work because it is too hard to isolate from human contact.

Good points. I basically followed RJ's lead (see below), but I stayed with the stuff during the process. The advantage of keeping an eye on it is that you can add some crystals every now and then to keep the solution "on the boil", which sped up the process significantly, compared to RJ's.

I didn't bother trying the wrestle out the stem remnants halfway either.

 

[mdvineng]

Yes, caustic is always an option. Once the axle and bearings are removed it will just be the BB body stuck in there, which one way or another can be gotten out. I would prefer to save the BB, but realistically that's probably not really an option.

I had naively thought that being unthreaded, it might actually come out okay, but this bike was obviously sat outside (or at least somewhere very damp) for a pretty long time in the past, and water has clearly done its damage. Somewhat ironically the BB itself actually feels perfectly fine, so it's clearly very well sealed (I've read these do have a reputation for lasting a long time).

Anyway, this is a longer term project, so I may not get around to doing it for a little while. I'll update when I do manage to make any progress, just in case anyone else has the same issue in the future.

I have a spare outer shell if required.