I didn't think of this until I read today's posts: I had a Chevelle that got a door banged up, and when I got it back fro the body shop, the door opened fine, or so it seemed, but had a problem closing like yo describe. I futzed around with it for a while, then on a whim, I just lifted up on the handle and the inside with both hands and closed it. "Snik, snik", it closed like butter. Took it back to the shop, and they made it right; the hinge had got slightly bent, and the bushings in it were worn a bit, and the combination made for the problem.

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