Aggitator won't turn. I assume I need to remove it and see if it is locked up, or if there is a pocketful of change etc...blocking something. My problem is I cannot get the plate cover off the post. I removed the screw and have used hooks through the holes with vinegar in the center and pulled like a mule...can't get it off...advice? Bought air pads to pump up but can't get them in between the cover and the basin...