A puller isn't actually needed. Lift the long part of the wiper arm up 90°, so it's sticking up in the air, then gently rock the mount back and forth while pulling up. The spring tension when the arm is laid on the glass makes it nearly impossible to pull the arms off by hand, but when the arms are sticking up into the air, there's no tension to hold the wiper arms onto the shafts and they come off easily. Figured that one out when I had to replace the front struts last summer, lol.