windshield wiper arm - 2002 monte

[foxxtrot]

Wife tried to use her windshield wipers and the drivers side works fine. The passenger side arm assembly is blown out it seems. Motor works fine, but the arm itself is stripped out where it meets the motor. I took the cap off, unscrewed the bolt and attempted to take the arm off. It doesn't budge? How do I take this arm assembly off so I can replace it??? It seems to be stuck on there?

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