Help: Really, Really Stuck Crank Bolt

[Tallpaul]

If have a really stuck non-drive side crank bolt in an ISIS BB/Crank.

First I rounded out the 8mm allen head.

Then I soaked it in WD-40 overnight, drilled a hole in it and wound in a LH threaded tap, which snapped.

So now i'm stuck with a bolt with a rounded head that's recessed due to the crank and I can't drill out as it has big lump of hardened steel stuck in it :twisted:

I'd still like to save the crank arm, any ideas?

 

[gibbleking]

it will cost you the bb the method involves cutting thru the bb axle with a carbon steel blade ....once thru then smack the offending bolt thru the crank arm...use an electric pad saw thingy to do it...hell even a jig saw on slow with cutting lube should easily do it,

 

[PurpleFrog]

I'm the last person to claim aptitude in the field of velocipede repair, but my general mechanical ineptitude does mean that I have a friend that may be able to help. His name is "Mr Two Ton Epoxy". If there's enough of a stub or socket or what-have-you to epoxy a suitable lever to, then the join might be strong enough for you to apply suitable torque. Say with a hammer.

You will have to rig the drying epoxied thing so that is completely tight and stable overnight - and make sure that no epoxy gets in the joint, or you are f##ked. With a big stick.

It's a long shot, but Mr Epoxy is good at those. The Devcon 2T epoxy is especially good.

 

[xioly]

I have a similar problem but got the allen head out - since then, i've burnt out all my drill bits so I'm off to B&Q tomorrow for more - looks like you'll have to chop off the axle..

Good luck.

 

[richardf]

chopping off the axle worked for me, but I got through many, many hacksaw blades in the process and had to have two separate attempts on it :cry: :x

 

[Grannygrinder]

.

For cutting purposes you will require, 1 4" angle grinder and 1 1mm thick cutting/slitting disc. If you have the clearence this will make short work of the BB. Better get 2 discs just in case. Taps are brittle(as you have found out) and as a result don't like being hit with a hammer. If you can get a very hard, small round punch, use this in conjuction with a large hammer.
Hit in to the end of the tap very hard and little bits of tap should break off, eventually alll the tap will come out and you can try plan A again

 

[REKIBorter]

Swear at it very loudly until it gives in. If that doesn't work threaten it with Vanessa Feltz

 

[dyna-ti]

Simple-
Saw off the bottom bracket axle between the crank and frame
Then knock the stub out the crank,you do this by-
First drill a large hole through a piece of 2x4 so it wont damage the inside of the crank,place the crank arm against the hole,so you have a solid surface to brace the crank on while you knock it through using a hammer + punch
Depends on the quality of the cranks,but id rather lose a BB than a crank arm

 

[Crell]

Have you tried mechanic's friend?

 

[Scrat]

Drill a 5/8" hole in a piece of 1/4" plate 12" or so long, peel out the rubber/plastic seal around the offending bolt.

Line up the hole with the rounded out Allen head, weld through the hole into the bolt up into the flat bar,

Let cool!

Undo,

or you could even try welding said rounded Allen Key onto it, bear in mind this takes more skill to NOT melt the crank.

I'm not sure how cutting the Axle is going to help? you will still have the stuck piece in the crank, yes you'll be able to get the BB out of the frame.