W202 Wiper Problem

[A17 LTF]

I have noticed recently during the bad rainy weather we have been having that the wipers are behaving quite odd. They still work but they slow down as they get to the middle of the window and then slowly go to the other side and this process repeats itself. Sometimes it is dead slow and then it speeds up again to a slightly faster speed and then sometimes it works normally.

Am i right in assuming the motor is knackered or is ther more to it than meets the eye?

 

[DITTRICH]

The mono wipers have several maintenance threads complete with photos.
Just search the forum.
Basically the plastic cover needs to be removed to expose the mechanism which needs to be completely cleaned and then re-greased. Other than that, the carbon brushes on the motor may well be worn. I've never read anything about people replacing the brushes as opposed to just getting a new motor but it seems silly to replace the whole motor just for the carbon brushes.
The wiper mechanism is not on any Mercedes service schedule so is unlikely to have seen attention since the car was new. A replacement mechanism from MB is expensive although enough w202's are being broken now to make sourcing a 2nd hand part quite easy. My mechanism has been cleaned twice by myself over the years (every 4 years) and at 178,000 miles both mechanism and motor are still okay.
Les

 

[A17 LTF]

Thank you Dittrich, i will try opening the mechanism and see if cleaning it out has an effect. Otherwise i may have to go to a breakers yard nearby.