Crank arm pinch bolt

[V12man]

Soak hole overnight with penetrating oil. Drill 2, then 2.5, then 3, then 3.5mm holes through bolt head, and use easy out slowly, the same way you would a tap i.e loosen out a bit, run forward a bit, loosen out a bit, run forward a bit until bolt is free. That would be the most extreme, normally just drill 2.5mm hole and easy out (even with Midas quality-level easy outs)

Worked for me over many years on aircraft, bicycles, forklifts and earth moving equipment, so you should be OK.

I never start with an easy out.. broken a couple in awkward spots before... that Bolt has a fair amount of torque applied to spec tightness - I wouldn't be surprised if that has been a touch over tightened too...

[ichnusa]

Remember to put the other side's bolt in and tighten it nicely before trying to remove the stripped bolt.  It will take some of the pressure off the stripped bolt so that it releases more easily.

[Eugene Brown]

Remember to put the other side's bolt in and tighten it nicely before trying to remove the stripped bolt. It will take some of the pressure off the stripped bolt so that it releases more easily.

Really good point. Also, if it's seized dead, maybe start drilling a 3mm hole from the bottom end ie opposite the head. When the bit bites, it may help to break the seize.