The trick I've seen used (and will likely be using myself soon) is to apply pressure with a long crowbar to pretension the bolt to come out then smack the arm sideways to make it "ring" like a turning fork. The vibration works the beveled post free.

Wouldn't hurt to get some liquid wrench into the joint first.

I remember changing the front thrust bushings and one of the arms just wound not come out. A good workout with the 3# hammer and my persistence paid off but I didnt learn the trick above until later.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)