You could try greasing the top of the self-extracting bolt; there is a lot of pressure/friction between it and the FC-35 and some lube might help provide just that little bit of extra pressure that could pop off the arm.
Squirt in some penetrating oil to lube its threads as well.
You could also see if you can get a pair of Jacobs chuck wedges behind the arm to add their pull to the extractor.