Stuck UN72 Bottom Bracket

[Trebz]

Hi All

Well what another fine mess i've gotten myself into.

So, UN72 BB firmly stuck in a steel frame. Have tried GT85, WD40, heat, cold banging and swearing. Also tried Coca Cola down the seat tube.

Basically, the teeth in the BB cups are demolished. The removal tool just spins in the cup now.

Can I remove the spindle somehow then hacksaw the BB cups out of the frame BB shell.

It'd be such a shame to throw the frame away because of this.

Oh, BTW, the seat post is stuck as well but that's another story.

Thanks in advance.

Trebz

 

[DanD]

Re:

If you can get it to me mate il get it out for you

 

[marc two tone]

Re:

Trebz. if there is enough of the seatpost to grasp, i.e all of it, just stuck. Then i would be happy to try shift for you. I've a 100% success rate with freeze treatment!

Then you could pour caustic down tube, i'm sure un72 cups are aluminium.?

Give it to danD first though, he has access to workshop stuff.

 

[rjsdavis]

Re: Re:

Trebz. if there is enough of the seatpost to grasp, i.e all of it, just stuck. Then i would be happy to try shift for you. I've a 100% success rate with freeze treatment!

Then you could pour caustic down tube, i'm sure un72 cups are aluminium.?

Give it to danD first though, he has access to workshop stuff.

I've got a similar problem...

At the moment, I've a Shimano sealed bearing bottom bracket. I managed to the get the adjustable cup freed up and out, but the fixed cup is stuck solid.

So far, I've managed to snap the jaws of my favourite original Campag 32mm spanner with my bare hands, twisting on the Shimano BB tool. On the one hand I was impressed I was stronger than the Campag tool, but on the other, was gutted as I've had it for years and I nearly threw the frame out through the window in temper!

Then, I installed a small vice that I've had knocking about for years.... Snapped that fecker too! To be fair it was only a wood vice, but still, I thought using the frame as the lever, the cup would eventually go!

Good news, is that the teeth on tool and b/b shell are still fine. It's be well lubed with "Crack It" freeze spray and liberal use of GT-85. My plan is to get a bigger "proper" vice, bolt it onto the bench and try again - however, any ideas?

The guy in LBS is off with a duff back at the moment, otherwise I'd have popped round there for his bench vice. Anything else I can try short of a proper vice?

PS - the Shimano B/B is in an old Alpine Stars Al-Mega frame - is this not ally on ally?

 

[Woz]

Some good pointers here: viewtopic.php?f=1&t=303406&start=30

 

[rjsdavis]

Thanks for the link Woz - had a good read, but I'm defo not at the stage of cutting out the BB as it stands. I'm expecting the BB to come out in one piece and be re-used. I've got a feeling that it's a UN90 (M900 XTR), and therefore well worth saving!

As said, it's stuck in place, however the non-drive side did come out (just from elbow power in my pre-shredded Campag spanner!) although it wasn't easy. The drive side should be similar (ish), but is a bit tougher. I'm confident that a proper vice and using the frame as the lever will break it free, I was just hoping for a trick of the trade before I can get access to one....

 

[02gf74]

Can yo not use the bolt for the crank and large washer to hold the tool in pkace, then 1/2 in or bettwr 3/4 in breaker bar with socket?

Ps if you are local i have 3/4 socket set yet to be used in anger and air windy tool.... no good if the teetb are gone on the bb.

 

[coomber]

Re:

Tack weld nut onto bb. Worked a treat.


Seatpost should be easy enough.

Re bottom bracket..

Wd40 and gt85 wont do anything to loosen the bond. Coke will but needs a really long Time to effect it. You need proper penetrating oil applied 2-3 time a day down seattube and from outside frame.

Heat works wonders too on stuck bb but keep moving the blow touch else paint will be effected. And no good on alu frames..

 

[backontheroad]

regarding loosening agents atf fluid + acetone 50/50 mix is good

 

[coomber]

Re:

Should point out the paint was gone already on the bottom bracket shell pic above.