Thanks for all the good advice. My local auto parts store had nylon locking nuts that were just thin enough that the stud on the wiper mechanism could "catch" most of the nylon. And, yes, several minutes of brushing with a stiff bristle brush cleaned up the splines (when I started, I thought the splines were worn out, but it was just accumulated aluminum shavings).

Intelligent of Volvo to make the wiper arm base the sacrificial part; I'd rather not have spent $200 and several hours on the wiper mechanism itself.

Do not forget to use a sharp pointy object and scrape
all the soft metal out of the shaft splines.

The Volvo wiper system was designed by kindergarten students in Gotenburg. Very poor. I keep a 13mm wrench in the drivers door pocket for just the situation. Klaus has a good Idea with the plastic nut. If the splines are wore from using the wipers with loose nuts you will need to replace the wiper transmission, which is a 172.00 volvo part and a couple frustrating hours. Keep rain x on the windshield and don't use the wipers to move built up snow. I'm thinking of drilling and tapping a hole in the side of the arm and screwing a small pointed screw into the spline, but I will try klauses fix first.

Take the nut that holds down the wiper arm and go to a hardware store. Match it with a nut that has a plastic insert to keep the nut from coming loose again. Yours just came loose and needs tightening again, and again, and again...

As for mounting, there are little white dots in the blacked out portion of the glass. The rubber is supposed to sit on them when you tighten the arm down.

Klaus
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