Cutting new spline for wiper arm. Bush Fix. Alfa 159 or any other wiper.

This worked for me. Spline was bald on alfa 159 wiper arm. Took the chance and it worked. 5 minutes. The metal is purposely soft on the wiper arm. Make sure saw is straight and thin. I made about 10 grooves.
Worked fine. Make sure spline on wiper linkage is clear also. All it wants is something to grip onto.
Not a mechanic. Just gave it a go.