Frustrating BB Problem
 

This is damned frustrating...

I'm rebuilding my 'cross bike with Campy Centaur components. I've stripped everything, but I can't seem to get the bottom bracket to budge. It's a Shimano UN52, and when I tried to loosen the drive side BB cup [English thread, loosen clockwise], it just doesn't move. How stuck is it? I tried with the torque wrench and I torque a whole lot higher than the 70nM it was supposed to be tightened to. I tried pouring hot water over the BB shell -- nothing... I don't want to force it or break anything, but I'm at wit's end here. This should not be this difficult. In fact, the left cup comes off pretty easily.

Any ideas? I'll even accept ideas that result in the destruction of the BB; I was planning to use it on another bike, but I'd be happy to get another, if necessary.

One more thing... am I right that the cups on the BB-UN52 are plastic?

Are you torquing in the right direction? English threads should be counterclockwise to loosen on the drive side.

Actually, English tightens counterclockwise on drive side. It loosens counterclockwise on the left.

You have loosened the non drive side cup or lockring?? The un52 I have seen are steel or alloy on the drive side. My never fail method.Lock the removal to the cartridge with a QR skewer of a bolt and some washers. Maybe some penetrating oil.Ditch the torque wrench.Long wrench handle or a cheater bar. Sometimes some hammer raps on the wrench handle.

if its stuck due to lack or removing and greasing threads, spray some penetration crap in there if you can and let it sit.

or invent a gizmo that lets u hook it up to an air compressor and blast it out

Pokey... Good idea! I didn't look, but I presume the spindle is hollow right through. One question, though... how do I anchor the frame, so I can torque out without damaging it? The workstand isn't sturdy enough...

two stands. one holds the top tube. the other holds the seat post tube. urr frame shouldnt move.

you could try breakaway or some other freeing compound.

I had this problem once. Break Free and a cheater bar worked. A UN 52 has steel cups so unlike the UN 72 with alu. cups it will not strip out as easily.

I messed up.The skewer won't work,cause the un-52 is not hollow like the un72.You will have to find a long enough metric bolt to hold the tool the the carteidge.My bad.

Have you got it loose yet? If not, you might try turning it counter-clockwise slightly to see if it will break loose that way. Sounds wrong I know, but it's worked for me before in other applications.

You'll need to apply more force. Clockwise to remove is correct for the right side.

My preferred tool for this is a long flex-handle Craftsman 1/2 ratchet. The great thing about the flex handle is that you can set it so that your hand is pulling in the same plane as the ring, so the tool doesn't tend to cant sideways.

UN52 rings are plastic on the left side only. The right side is steel, and is part of the housing of the BB.

Good luck!

Sheldon

Wow! The Master speaks! Welcome Sheldon! :)
Hope you stick around.
I was just at your page a few minutes ago looking for sage advice about this problem.

That "nebie" under Sheldon's name is a kick!!

This is great, welcome.

Thanks, everyone.

I can see that this is not an unusual problem. My main fear is that I will damage the frame or the threads [if I do, I'm buying an Empella]. There's a wrench shop around the corner from me, and I'll see if the wrench can help me out with this.

Wow, is this for real? If it is, I want to say hi and welcome Sheldon! I've gleaned tons from your site. Your presence here would be huge, equivelant to having Armstrong start posting in the race forum IMHO.

Some penetrating oil and a little heat may help-just don't burn off the paint, or quench-harden the shell.

FWIW, if that WASN'T St. Sheldon, he did get all the phone numbers and URL's correct.

If you clamp the frame itself in a repair stand and apply heavy leverage to the BB, it could conceivably dent a frame tube if there's nothing inside (meaning, the seatpost doesn't go that far into the frame).

If you get a big breaker bar or ratchet for leverage, one possibility is simply to lean the bike against a wall with the wheels on, position the breaker bar at the 3 o'clock position, and push down. This puts the stress where the bike's made to take it. Alternate idea: loosen the repair stand's clamp-rotation lock so you can rotate the bike and clamp in the stand without too much effort (as a "safety valve") and then use the frame and wrench as opposing levers, rather than relying on the stand to counteract your effort. Not likely you'll dent the frame with your bare hands :)

Unless your frame has unusually delicate threads, it's not likely you'd damage them unless you cross-threaded the BB and forced it in.

If you hold the BB tool onto the cartridge using a bolt and washer, that works great, but the bolt does prevent using a ratchet or breaker bar. In this case you would want to pick up a wrench that fits the flats on the outside of the BB tool, or perhaps clamp it in a bench vise and use the frame for leverage.

put the BB extractor thingy in a vice.. then put the bike on top of it and turn the bike.. u can get a million times more torque by using the bike to loosen it than a wrench. i do that with freehubs and cassettes as well. easier to turn the whole wheel then a wrench

So ... how did you go V'pedio ..what was/is the outcome ? .

I got the BB out by putting the tool in a vise and turining the bike. It had been assembled -- by Kona -- without anti-sieze or grease on the threads. Since then, I have replaced the BB again, this time with one with a longer spindle to accomodate the oversized, wide-spaced chainstays. Rides like a dream... a muddy dream... :D