Bottom bracket removal challenge

[battered]

I'm having a frame blasted and powder coated, so I'm stripping down. All OK, done it before. The BB was difficult. So with the special socket held in with a crank bolt to it wouldn't pop out, I got the socket clamped in the big vice. This is not my first rodeo. Been here before, and all that. First up, the lockring disintegrated. It's some plastic affair stamped "Made in Slovakia". OK, try the other side. Same again, the bit that normally unscrews has disintegrated, more black plastic. Normally they are steel, bizarre. Obviously it was some junk that was intended to be used on a "leisure bike" that would be thrown away after a few years of riding to the shops, so nobody was bothered about dismantling it in years to come.
I know which way each side is handed so I was going the right way.

So these are my choices, in ascending order of cost and pain:
1. The bearing still works, the cranks will go back on. Clean it all up, tape over the moving bits, get it blasted and coated and simply reassemble it. It will work. If the BB ever wears out, worry about it then. This might take a while, I use the bike a fair bit but it's local stuff.
2. Take it to a shop.
3. Get the engineering tools out and start drilling and chiselling, replace the BB.

Have I missed anything? How much pain and angst is involved in removing a square taper BB when the bit where the spline socket engages is no longer present? At the moment Option 1 is looking attractive. If the bearing were done, I'd have started on Option 3 already, but I don't want to risk trashing a frame that I just enjoy using.

 

[GuyBoden]

If the cups are plastic, I used a very Hot soldering iron and melted the cups.........
Or just heat the whole thing with a flame thrower, if you are painting it anyway.

Edit: Don't over do it.

 

[battered]

Thanks. OK, I can do that. With a smaller flame. :-). Once I have melted the cups, then what? Will the bearing(s) simply fall out, or will I have a screwed in steel insert that has no obvious means of unscrewing to deal with?

 

[GuyBoden]

Melt both cups, the cups are threaded and hold the BB in place, so without the cups the rest of the BB will pull out, then remove any residue plastic from the threads.

Are both cup sides plastic?

 

[T4tomo]

Hmmm, if the threads are some sort of metal, bonded to the plastic bits you'll have an issue though...

 

[GuyBoden]

Hmmm, if the threads are some sort of metal, bonded to the plastic bits you'll have an issue though...

They are usually all plastic, I melted the cups and got it out, it took a bit of time.

This (below) was similar to the type I had in an old frame, a big advantage of a plastic BB is that it melts.

 

[Milkfloat]

I would not spend money or effort getting it painted/coated if you know you will have an issue with the BB in the future. I would get the BB issue resolved first.

 

[battered]

I would not spend money or effort getting it painted/coated if you know you will have an issue with the BB in the future. I would get the BB issue resolved first.

That's a disturbing amount of common sense.

 

[battered]

They are usually all plastic, I melted the cups and got it out, it took a bit of time.
View attachment 592118
This (below) was similar to the type I had in an old frame, a big advantage of a plastic BB is that it melts.
View attachment 592119

That (top) looks very much like what I have. I'll do the sensible thing, the other factor is that if I send it for coating with the bearing in and the bearing loses its grease at 160°C, the powder coating won't stick to the greasy metal. Keep me covered, I'm going in.

What do you reckon for the melting, poke it out with a hot bit of steel or did you stick a flame on it? I can of course put a flame on the square taper and let conduction do its thing.

 

[GuyBoden]

That (top) looks very much like what I have. I'll do the sensible thing, the other factor is that if I send it for coating with the bearing in and the bearing loses its grease at 160°C, the powder coating won't stick to the greasy metal. Keep me covered, I'm going in.

What do you reckon for the melting, poke it out with a hot bit of steel or did you stick a flame on it? I can of course put a flame on the square taper and let conduction do its thing.

You could use a glowing red hot heated sharp screw driver, see if it melts the plastic, but as I said, I have a large soldering iron, once the soldering iron is heated for 10mins, it is hot enough to slowly melt the plastic. A heat gun might work too. Be patient, the plastic takes time to melt.

 

[T4tomo]

I'd defo go for the sticking some hot metal thing on it, rather than a naked flame, its a bit more controllable

 

[Milkfloat]

I'd defo go for the sticking some hot metal thing on it, rather than a naked flame, its a bit more controllable

Less fun though.

 

[battered]

Well, I'm in progress with the soldering iron. What a bloody chore. If I'd known I would have postponed the job for another year. Still, it seems to be working. I have the bearings exposed on one side, the plastic does go all the way to the aluminium of the frame, which is a relief. If there were a steel insert I'd be in trouble. More melting might allow me to lever the mangled bits out. The other option I'm exploring is smacking the races out using blows to the square taper, it's shuffling back and forth a few mm. I'd like to do nasty things to whoever specified a plastic BB.

 

[Big John]

It's an antique, that BB. Shame you've had to torch it. I think FAG used to sponsor a TDF team back in the day 👍

 

[battered]

It's an antique, that BB. Shame you've had to torch it. I think FAG used to sponsor a TDF team back in the day 👍

I don't think mine is a FAG. Made in Slovakia job, it's been OK for an item that was intended to be wound in once and forgotten about. To be fair it's still OK, or it was. If it weren't for recoating the frame, it would still be OK.