Getting a broken BB cup out?

craker

So I must have tried undoing it the wrong way.

Square taper Shimano BB, non drive side plastic cup. It's broken in half, the bit with the splines has come out. What's left is stuck inside the BB shell. Nothing to get purchase on to unscrew it.

The frame is alu 7005 btw.

rubbernekker

Is the rest of the bb out?

If yes- no problem get yourself a blowtorch or just a gas hob and with gloves heat up a butter knife and carve out a small section, or if you have a soldering iron just melt a few cuts into the plastic sleeve until you can lever it out with a screwdriver. You can use the blowtorch on the frame directly but your paint may not survive.

if no you may have to use the blow torch on the frame to get the sleeve to deform enough to get the rest of the BB out.

rubbernekker

why a butter knife? because everyone has one and they aren't sharp enough to ruin the thread. lots of insulation though!

craker

I'll give it a go.. thanks

nicklouse

an easy way shown here

http://www.bikeradar.com/forum/viewtopi ... c&start=60

andy_wrx

Yep, like Nick says.

andy_wrx

Yep, like Nick says.