The wiper on die Frau's '95 C-220 has developed a strange problem. On any setting, between the ten and two o'clock positions, it moves very slowly, and then speeds up. Upon further observation, this is where the arm retracts to clear the top of the windshield. It also makes a "chunk" sound when it changes speed.

The blade is in good shape, and the glass is clean. Do not believe that it is resistance from the glass.

Relay? Motor? Anyone seen this before?

Thanks as always.

I have seen this a number of times. The fix is this. Take off the blade. Then take off the plastic cover on the top of the transmission. (This is the black cover at the base of the blade).

Now clean and lubricate inside there.

(At the dealer, they replace the whole unit for this)

The wiper's pin that makes the vertical up- and down movement possible, has to be lubricated regularly (we normally do that during every service...) to prevent the system from getting a hard time (as described).

http://members.tripodnet.nl/mbenz/1ef63b10.jpg
If you remove the black plastic cap (start pulling at the bottom, whilst widening the cap, and rotate out the top) you will see the metal colored wiper part as in the picture above. In the middle is a pin that will go up and down when you (manually) turn the wiper over the windscreen. Clean and lubricate it when it is in the most extended position.

good luck & greetingz,

MBenz: How do you MANUALLY turn the wiper?
 

Hi, MBenz:

How do I manually turn the wiper over the windshield? Any tips? (ignition 0, I, II, etc?) Thanks.

Ok. I had to do this to, and it's easy.
Turn the ignition to 1 or 2, turn the wiper on, when the wiper is on the passenger side of the vehicle, take the key out so the wiper stays where it was left when car was turne off (ie passenger side of car). Then remove cover, lubricate, and you can guide the wiper manually when it's left like that and not in the parked position. GOod luck.

At dealer WE replace the gearing only when the plastic outer gear is broken!! Many times this WILL burn up the motor & switch as well.