Part of what is holding them back is the side pressure exerted by the force of the spring holding the wiper to the windshield. I am not sure how you can relieve that completely while the hood is open, but I think that I have been able to strike my stud with a nut left on the outer threads with a nylon hammer while taking some of the tension off the wiper's arm, and had them lift off. That was my first time. The second time, I needed to put a small amount of puller on them. I think that a batter post puller would do the trick, but I used a pitman arm puller since I didn't have the battery post puller. It surely did not require much force with that puller before the arm slid off the stud.
