I have an Ultimaker 2+ which had stopped feeding, so I disassembled the feeder to clean it out, and now I am finding that the tension spring refuses to re-tension. As far as I can tell it looks exactly like the pictures in the assembly instructions say it should, except that when I close it back up and go to tighten the tension screw, the screw will go down into the nut but this does not have the effect of tightening the spring. The nut isn't stripped, and it was at the correct tension mark when I disassembled it. The ledge at the bottom of the spot for the tension screw is deformed slightly as though the screw has been pressing into it.
Does anyone have any suggestions about what this could be/things I can try to fix it?