Seized and shredded bottom bracket

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  • I am in a pickle.

    My BBT-5 in a vice shredded the left cup on a Campagnolo square taper bottom bracket.

    Horrific phone picture for illustration:


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    • IMG_20201216_002226.jpg
  • What is yer boy Ndeipi gonna do?

    The right hand cup is still intact but it is not moving either. I could try soaking the RH cup in penetrating oil and then try removing as normal. Any recommendations on a good oil?

    As for the shredded LH cup... I've seen chat about drilling small holes in BB cups and increasing their size with ever bigger drill bits until you've chomped right up to the BB shell - which can then be extracted with a bit of cutting and knocking I guess?

    Or for less drama could try soaking the LH cup and drifting it out.

  • Could drill a couple of holes and use a pin spanner. I’d go as big as possible on the pins / holes

  • I think I'll not be able to get much force on the cup using a pin spanner. Much less than the BB tool anyway. Maybe if it's really soaked in penetrating oil, for days, it could work.

    Though I could maybe fashion a beefy pin spanner of sorts by standing two strong rods in a vice and drilling two matching holes in the cup.

  • . Didn't look at the pic properly

  • Yeah, or make a tool with two 10.9 high tensile short m6 bolts through a bit of flatbar. Something like this - might even be able to use an angle grinder one if the pin pitch fits.

  • I will first try to release the RH cup, which is not mashed. This will get the BB cartridge out with the spindle leaving only the LH cup. The RH cup is seized as well though, so I'm planning to:

    1) Spray Plus Gas down the seat tube, leave for 24 hours, add more, repeat for 2-3 days

    2) Chill the whole BB shell area to near 0°C in a tub of ice water. Aluminium BB cups should shrink more than the steel BB shell.

    3) Use the BBT-5 in a vice to hopefully release RH cup

    4) If this fails then I'll maybe buy some Loctite Freeze & Release which can go down to -33°C.

    5) Then I'll only have a stuck LH cup which I can hopefully release by drifting it out, or by using the angle grinder pin spanner, or by some other more nasty method involving drills and hack saws. Sheldon has a neat looking method involving a beefy bolt, several washers and a nut. I love how, 10 years after first reading it, the Sheldon Brown website still teaches me new things.

    If I destroy the RH cup teeth before releasing it then I'm in real trouble. I could perhaps eat away at the face of a cup and pull the cartridge out, then hack saw that cup out and use Sheldon Brown's method (above) on the remaining intact cup.

  • Sounds like a lot of faff ... if you can get the DS cup out, it could be solved in half an hour with a junior hacksaw / dremel and a bit of flat bar.

  • I'm guessing you grip the flat bar in a vice and rotate the frame?

    ... if you can get the DS cup out

    Yeah this is the hard part requiring the faff. My DS cup is seized to the point where the BB tool teeth are just starting to strip the teeth in the cup, as it's an alu cup.

    Anyway, I'll order the Plus Gas and report back after some soaking.

  • Yeah plus gas, and when you're using the BB tool, make sure you clamp it into the BB with a bolt so it can't slide out and tear.oit the teeth

  • The sheldon big bolt method is your best bet here, if you can get the rest of it out.

  • I use a QR skewer to hold the tool in place. That still resulted in a shredded NDS cup, but I know that simply because it's made of cheese.

  • Ok now I've shredded the DS cup too. Didn't withstand force from the BB tool.

    So now my option is perhaps to drill two holes per cup for an angle grinder spanner.

    Anyone got a better plan before it do that?

  • Just because I’ve seen it happen, you’re definitely undoing the cups in the correct direction, right?

    Hopefully you’ve managed it but I’m wondering if you’ll be able to apply enough leverage with an angle grinder spanner without it popping out as you torque.

    I’d have a crack at that method, just to see if it works. If available try using a >1m pipe on the spanner for leverage, with wd40 on the cup. If that doesn’t get it out, I’d move straight onto dremel cutting wheel, cutting the cup into 4 or 6 pieces and gently pushing/prying them out without damaging the threads.

  • I gotta buy an angle grinder pin spanner.

    I should really mount the pin spanner it in a vice. And first, I think a QR skewer through the BB spindle can hold the pin spanner securely into the cup.

  • Depending on how much you value the paintwork you could go down the route of soaking it in caustic substances.

    Maybe start with Coke?

    A window box type thing from the garden centre is good for soaking the bb area.

  • Is the shell steel or aluminium?

    Last resort method of mine is tack welding a metal bar to the shell to turn it out. 100% success rate.

    Can fuck up your paint sometimes though and it’s easier to do on steel.

  • @LeChef Aluminium BB cups. I wouldn't be too precious about small paint blemishes from tack welding, though I think finding someone to weld an alu bar the the cups might be difficult.

    @M_V If I rule out all other options I will then go the caustic route. I like the paintwork on the bike so this would be a shame. I still have some caustic soda since I released a seatpost from the tandem. Thanks for the window box recommendation. Could I save the paint by pouring caustic solution down the seat tube and then standing the BB area in a window box of water while it works? I would hope that the water would stop any seeping caustic solution from sitting on the paint work long enough to hurt it.

    Though I'm not averse to repainting the frame, it's just £150-200 that doesn't need to get spent on this project. And the paint is so nice already.


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    • IMG_20201218_105821.jpg
  • Caustic stuff from the inside out is a good idea.

    Paint is really nice so would indeed be a shame to ruin it.

  • If you can get the other side out you should be able to knock the axle and bearings out and have access to inside of the seized cup to get some penetrating fluid where it needs to be.

    Alternatively and somewhat controversially, you can sometimes use the cartridge to force the cup out with a massive hammer. If the shell and threads are steel and the cup is alloy then you stand a chance of being able to use brute force. Worst case scenario you may need to get the BB threads chased.

  • Both cups have shredded teeth at this point, so something destructive has to happen.

    I like the massive hammer approach in principle. I think there's a real risk of damaging the frame but perhaps if I use a drill to attack the cups first then I can remove some metal and it will take less force to knock the the spindle out. It is the idea to bash out most of the alu cup in the same process, leaving behind only slithers of shredded alu threads in the steel BB shell?

    I reckon my plan is to work through in this order of increasing severity:

    1) Drill NDS cup with two holes for an angle grinder pin spanner, try to extract

    2) Drill DS cup the same, DS side

    3) Drill many more holes in the DS cup and attempt to hammer spindle through from NDS

    4) Drill much of the NDS and knock from DS

    5) Caustic soda down the seat tube

    There is another question... Should I spend £8 on a can of "freeze release" so that I can get the BB shell down to -30°C for steps 1) and 2). I'm leaning towards "yes".

  • Definitely rotating the correct way.

  • the hammer option seem like it would blow out the BB cup before the thread gave way, given what we've seen so far. either that or the repeated hammering would end up damaging the frame in some way

  • other than than, sounds good.

  • There is another question... Should I spend £8 on a can of "freeze release" so that I can get the BB shell down to -30°C for steps 1) and 2). I'm leaning towards "yes".

    Why do you want to contract the metal BB shell? Contracting the cups is more likely to help release.

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Seized and shredded bottom bracket

Posted by Avatar for Ndeipi @Ndeipi

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