Getting crank off

[Gravity Aided]

Alternatively as a work around you could try is a nut that just fits inside the opening, you should then use the smaller end.

I used an extra brake washer and a regular puller, last time I removed mine.

 

[rogerzilla]

The insert is usually called the "mushroom". I haven't used it in years because Octalink was a dead-end tech; the splines worked loose.

 

[Gravity Aided]

Mine haven't, but when they do, I'll probably go GXP.