Originally Posted by RookieRoadie

Uh Oh... the only thing I can think of is trying some sort of gear puller, but getting enough purchase on the crank could be a problem. About the self-extracting bolt, the top cap is usually threaded as well and it screws into the crank, so that undoing the bolt with allen head brings the crank with it. So if it was a self-extracting bolt, I don't get how you removed it while leaving the crank on the bb spindle? They usually look somethjing like this:


Just thought, with the right tap, you could maybe re-tap the crank - probably not a very helpful, or likely solution though...

[EDIT] Not sure if your crank is powerspline or square taper, but if it is the latter, could the square bit you mention be the taper in the crank that fits onto the bb spindle? I don't mean to be patronising, so sorry if that's not what you meant.