C180 Window wiper problem
 

I have an issue that ive tried to solve a few day now.

The problem is that the wiper is supposed to go inn an inn and out motion as it passes over the windshield from all the way inn when on the sides of the window, and out when its in the middle of the screen.

However the window wiper goes out and not inn agian, ive tried to grease the wiper mechanism but with no success.
It seams like the rotating arm that pushes the wiper extension inn and out inside the "turtleshell" spins on its own accord.

Anyone have any suggestions?