Shuddering monoblade wiper -- W124
Does anyone else have a problem with a noisy single wiper on a W124? Mine has been very annoying for a long time. At both ends of its travel, just before it reverses, it "shudders" and to a lesser extent squeaks. It seems to be due to the combination of moving in an arc and at the same time retracting (i.e., being pulled toward the wiper motor).
I've tried cleaning the windshield with lacquer thinner (to remove wax, etc. in the pits in the glass), replacing the whole blade, cleaning the blade, and using Rain-X, but with limited success. I've also put a little silicone grease on the shaft that provides the in-out motion of the wiper, and that seems to help a little, for a little while. Most recently, I heard that if the wiper blade was not perpendicular to the glass, it would squeak. I bent the wiper arm a bit to make the rubber insert perpendicular, but again no help.
Anyone have any other ideas?