Originally Posted by
HillRider
Yes, Ultegra Octalink cranks had self extraction crankarm bolts. Back off the bolt with a 8 mm hex key and after it turns a rotation or so it gets tight again. Continue unscrewing the bolt and the arm will come right off.
FWIW, you really need a dedicated 8mm hex tool on a 3/8" ratchet wrench to get these off. I found out the hard way that my Harbor Freight 8mm ball end t-handle was not up to the job.