All this, and all you had to do Roger was place a serrated lock washer
prior to the nut, on the face of the arm.

I think the tin foil will be short lived solution.

But a good idea.

RC

Subject: fix windshield wipers that wont stay in position
Hello, many vanagons that I have seen have windshield wipers arms that
can be moved about without the wiper moter being turned on.Dont know
why, but I have a soultion.Tightening them wont work(sound
familiar?).You've all ready tried that till the nut will just about snap
off.Some people may want you to buy new ones.Here's what I did.I took a
bit of common aluminum foil,and put this around the wiper shaft. I
removed the wiper arm first of course.This foil took up the extra room
between the shaft and the arm.I retightened the nut and the arm held
position like a new one.I think foil from jucy fruit will work too.Bye