[Closed] How would you remove a seized BB cup?

Melt it out with fire

Try a large and good quality strap wrench/ mole grips.

Or... Leave the cup in if reusing the frame and replace the bearing in situ?

I used a pipe wrench last time. Big heavy one that'll bite into the soft alloy cup.

I assume external BB?
Fire on the cup - differential expansion will probably break the lock.
Then a nice, big pipe wrench or preferably a large vice with attached bench.

Sawing through the cup but not into the threads will allow you to knock out the pieces. I've done it with a UN72.

Unless you go chemical/heat and massive leverage.

ACF50 might help with the corrosion that’s jamming it in place but as it’s a destructive methods, a big pair of Stilsons/pipe wrench will get it out - it might collapse in the process and you’ll need to cut it out.

I had this issus with a SRAM BB on my Cotic steel frame.

Ended up using a Dremel rather than the grinder as I could be more precise. Took a while...

BB in a desk vice and turn the frame.

There's always the chemical option. Caustic soda will eat the aluminium without hurting the steel. Its a slow process so I'd probably try something mechanical first then you have this as a fall back to remove the mangled remains.

OP
Is it both cups?
Before you go at it try soaking with paraffin/release oil in to the threads first.
If only using a wrench( no vice),double up with a screwed rod clamp arrangement at the same time.I have used emery paper scrunched under the clamp washers for extra grip.

Take it to a bike shop.

(See thread on four month bike shop wait)

At the risk of sounding silly, you are turning it the right way, aren't you?

Put a thick polythene bag round the cup , seal all round it with zip tie or tape .
Lie the frame on it's side and fill the bb with plus gas , diesel, coke .
Leave for a couple of days. That should help.

As suggested, soak it in plusgas, heat it up and if all that fails I have had success with cutting a slot in the external part, securing the frame and then drifting it with a cold chisel/lump of metal and a big hammer in the slot you cut.

Good ideas, thanks.

At the risk of sounding silly, you are turning it the right way, aren’t you?

"I've been doing my own maintenance for 30 years lad" etc etc (and look where it's got me!)

Blunt chisel and knock it. Round

Quiet often the only way to undo seized rounded nuts on cars n trucks.

The impacts the key....

(See slogging spanners)

Well that didn't pan out

Wow. So is that the bb shell ruined ?

At least you can bash it inwards now. The slots will let the plusgas get in there next time...

Well that didn’t pan out

Nonsense, you’re halfway there 😂

I'd try knocking it inwards with a chisel.

Otherwise I'd go down the caustic route. There's threads on it on here. I had success removing an aluminium seatpost from a steal frame that way so this should be a much easier task. As long as you can get creative with the masking to hold the liquid.

The threaded part of a HT2 BB shell is paper thin. So - drive out the bearing from the other side (or saw through the cup from the outside but this is highly likely to damage the frame)then cut some of the cup off (like you have already done) then smash the remains of the cup inwards with a cold chisel. As long as the bearing is out you can just destroy it, eventually you'll get enough of it bashed in that you will start to be able to pull parts of it out.

I feel your pain.
I've had success with Caustic soda on a few seat posts - just don't rush it.

Looks like you've cut into the frame too.

I don't believe you wanted to do that.

Edit: To answer the OP question, I'd use an extender tube from a Henry vacuum cleaner slipped over whatever tool grips the BB best.

3rd Caustic Soda, outside and in plastic washing up bowl, left overnight. That cut into frame is a shame.

You're basically there! And, er, the silver lining is that usually when doing this it's made much more awkward by trying to avoid any damage to the bb shell, well, worry no more on that score.

I'd get it all cleaned up, hit it with more penetrating oil first, you've got openings there that you didn't used to so it could work better than before. I'd personally zap it with a blowtorch from the other side ie into the BB shell but you do need to be careful of the paint.

The remaining bit of outer BB casing is now absolutely prime for hammering, if you get the bike on a bench or on the floor and really well set so it doesn't move, and just seriously slug that a few times with a big punch and hammer I'd expect it to move, or break. The amount of force you can get on it is basically limited by the size of your hammer and how secure you can get the frame.

But if that doesn't work, then removing the rest of that outer casing will leave the remaining part with very little overall strength and you should be able to just forget about turning it, and just crush the remaining bit with a vice or again with a punch and hammer, just get it on the remaining edge and smash it, fold it inwards til it goes like a clover. It'll be easier if you put some cuts into the inside of the tube with a hacksaw, you're not aiming to go all the way through, just enough to weaken it.

In some ways what you have there is perfect for these two approaches, and if it were me, I'd be pretty much 100% confident that one or the other would work. THe latter is seriously destructive but it lets you put a huge amount of violence on what is now really a small bit of metal.

Then, some thread clearout.

Which bit of "use a Dremel" did you miss?

I wouldn't heat it up. Aluminium expands more than steel. You could try cooling it down - I had success with obviously smaller parts by putting them in the freezer. It's going to be cold tonight, could you leave it outside then early tomorrow morning smack the remaining part in a tangential direction to get it to turn?

plus gas/WD40 and vice, twist the frame.

It is a shame about the cut in the frame, but I’d use that frame without giving it a seconds thought.
Chisel is the way forward, gently as you can, little bit at a time.

And run a tap through that before putting the new bb in, make sure it’s clean. Then copperslip it.

molgrips
Full Member

I wouldn’t heat it up. Aluminium expands more than steel.

The point of heating here is to break corrosion/galling (and usually to weaken threadlock but I think we're probably past that)- so the different rates of expansion under rapid heating are exactly what we want. Basically we're flexing the parts rather than having any hope of shrinking one away from the other.

It'd be better to do it with cold, if there was such a thing as an icetorch but there's no DIY way to get the same rapid and large temp differences with cold. With plumber's spray you can create maybe 20-30 degrees difference on the surface if you're lucky but it's less aim-able and way less powerful than doing the same with fire, I'd be guessing but I think if you could get 10 degrees to the mating surface that'd be a surprise.. Leaving it out overnight'll give you a couple of degrees and very slow rate of change. 10 degrees wins you about 0.000003mm of extra contraction in the alu vs the steel, I think. Whereas with heat, the limitation here is just protecting the paint so putting 250 degrees change to the mating surface is pretty straightforward.

I don't think it's going to make a massive difference either way tbf- I'd do it because it's easy. The hammer is going to do the real work.

Maybe, maybe not. Any got any liquid nitrogen?

As I said, slots sawed through or almost through the threaded part of the cup will allow you to collapse it with a hammer and chisel or similar. 2 slots at 90°, knock the smaller piece out, then hit the bigger piece (both radially) to decrease its size then it should be easier to get out.

I speak from experience.

That's the plan, Al. Ta.

It is a shame about the cut in the frame, but I’d use that frame without giving it a seconds thought.

I have no qualms about using the frame. I'm masking my annoyance having done it, though. The have went through the cups and BB shell like butter, expected more of a fight there.

Thanks for all the input.

I managed to achieve basically the same result you have by putting the bb in a vice and turning the frame. Completely sheared off the external bits

After that I carefully used a hacksaw blade to cut through the remnants of the bb, which got that out, then I got a lbs to chase the bb threads to clean them up. Was fine

Let mu be the first:

“I’ve been doing my own maintenance for 30 years lad”

Ahem. Ooops.

I'd go down the chemical route as long as the frame isn't brazed and you can find a suitable container in a well ventilated room.

It’d be better to do it with cold, if there was such a thing as an icetorch but there’s no DIY way to get the same rapid and large temp differences with cold.

You don't need a temperature differential. If the whole lot cools down then the alu will shrink more because it has a greater thermal expansion coefficient. Likewise if the whole lot heats up the alu will expand more.

I have had success with some stuck parts leaving them outside as well as the freezer method, but it was a long time ago and I don't remember what it was. You don't always need a lot of heat. I got the bearing out of a Race Face BB just by warming it up gently with a heat gun face down - bearing plopped out. Of course this is a bit different because the corrosion has expanded to put pressure on the BB shell so the contraction may not be enough in this case.

“I’ve been doing my own maintenance for 30 years lad”

Note the quote marks for a touch of irony!

As a pal said, this is a great advert for preventative maintenance. And it's first seized BB I've had in 30 years 🙂

Cut parallel with the BB axle thru the shell, not across the shell and frame?

That’s the plan, Al. Ta.

Cool, Godspeed.

Thankyou for this thread

Yesterday I gave up removing the BBS from my tandem when all 4 cups were seized in

I then read someone on here suggesting clamping the BB (or socket in my case for square taper) in a vice and turning the frame

I ran out to the shed mid evening film and used my nice large tandem frame as a huge lever and removed all 4

The mrs face when I got back in all triumphant and covered in grease at 10pm was worth it