Mercedes with single blades can dry up over time, which can lead to corrosion and eventual seizure. Mine was very dry.
If anyone can help me with a detail exploded view of the wiper transmission, there are six very thin shims/washers an I‘m not sure how to put them back in. To lube my wiper mechanism on my 1991 500SL 129 chasses I had to completely remove the wiper system which then allowed me to remove the three phillips screws holding the cover on. In some of the threads they say the cover is plastic and held on with two clips underneath. I my case my cover was metal an held on with three screws.
Thanks, Ron MB