W124 Windscreen Wiper problem

[Boltneck]

My W124 Mercedes has an annoying problem where the wiper blade noisily flops over to the trailing edge just as it returns to the start position. I have replaced the blade with genuine Mercedes and cleaned the windscreen but I can't stop it from happening. The wiper mechanism has been cleaned and re-greased but that hasn't made any difference either. I'm sure it shouldn't do this. Does anyone have any ideas how to resolve it?
Hopefully you can hear it and see it on the screen in this short video:

https://www.youtube.com/watch?v=0tQxzCEclKg

 

[optimusprime]

I think its trial and error .Clean the screen once more with methelated spirits . Is the blade 26" ? Only one i have used is Bosch .There was one fitted to the car when i had it first and i replaced it with the same type .

 

[Dec]

Can you put up a video as seen from the outside?

Dec

 

[brucemillar]

From your video.... I would think you have the "wrong" length of blade mounted and itr is fitting the side channels/windscreen trim. This happened on my 124 and I bought a blade that was 1" shorter than the published MB spec blade = problem solved. When the blade is parked, is it going under the windscreen trim channel?

To test it is not the mechanism making the noise: Remove the blade> Tie a rag around the arm, where it touches the windscreen > Switch on wipers and listen? If the clonking stops? You have your culprit in the blade length.

 

[CabrioDave]

Just went out to have a look at mine. Like Bruce, I think you've got the wrong length of wiper blade. When mine is parked, there's 20 mm of unswept glass between the end of the wiper and the edge of the windscreen.

 

[hotrodder]

As Dec can we have another vid (or some pics) from the outside with a wider view... current vid is too tight of a shot to be sure* but looks to me like the eccentric part of the mechanism is broken/stuck at full extension


* https://www.youtube.com/watch?v=EM-wbvRChfs the streaks on the screen give the game away and if you set the play speed to 0.25 can see the wiper extend and retract to reach further into the upper corners of the screen like it's supposed to

 

[brucemillar]

In hotrodders video clip we can see that the wiper blade is a good inch short of touching the windscreen trim/edges. Check that you have the same clearance.

 

[CabrioDave]

Ooh! How do you set play speed??

 

[hotrodder]

Click the settings 'cog' third in from bottom right and it gives quality and speed options
Slow down the OPs vid to 0.25 speed and look at the bottom left corner. Don't get a full view but from what is shown of the unswept portion in the lower middle of the windscreen the pattern is wrong. Paradoxically much clearer with a dirty screen...



ETA even clearer vid (no need to mess with play speed) of the same wiper on an r129 https://www.youtube.com/watch?v=HKGhKrQmK68

 

[CabrioDave]

Click the settings 'cog' third in from bottom right and it gives quality and speed options
Slow down the OPs vid to 0.25 speed and look at the bottom left corner. Don't get a full view but from what is shown of the unswept portion in the lower middle of the windscreen the pattern is wrong. Paradoxically much clearer with a dirty screen...

View attachment 63006

Thanks. Perhaps depends on device/application. Cog just allows quality change on iPad/Safari; no cog at all on iPad/Youtube
Will try later on iMac.

 

[JC220]

My W124 Mercedes has an annoying problem where the wiper blade noisily flops over to the trailing edge just as it returns to the start position. I have replaced the blade with genuine Mercedes and cleaned the windscreen but I can't stop it from happening. The wiper mechanism has been cleaned and re-greased but that hasn't made any difference either. I'm sure it shouldn't do this. Does anyone have any ideas how to resolve it?
Hopefully you can hear it and see it on the screen in this short video:

https://www.youtube.com/watch?v=0tQxzCEclKg

I just took mine apart to service it 2 days ago. I created this DIY also- at least you can see the inner workings for your info

HOW- TO: Complete windshield wiper mechanism lubrication + upgrade

Yes check wiper swept path as above. It could also be that if you had it apart the park setting is not correct & the wiper is over-reaching.

And if the linkage is badly worn (The bit that connects the motor to the arm) that can cause sloppy movement - especially at transitions in direction

 

[roadhog]

...looks to me like the eccentric part of the mechanism is broken/stuck at full extension...

Wouldn't that cause an issue at the top of the sweep rather than the bottom?

 

[hotrodder]

Wouldn't that cause an issue at the top of the sweep rather than the bottom?

Both but i'd have guessed it'd be more of an issue at the bottom corners (more/bulkier stuff to catch) than the top? Not one i've experienced personally, rebuilt/serviced several w124 mono wipers but all of them were just very sluggish/partly seized

Dunno if it's even possible to fit a wiper blade 'backwards' on these but on the offchance it is then the blade is not symmetrical but slightly offset, at least the Bosch blade on mine is. If it is possible then i can't remember if the blade clip/pivot is offset in a direction that'd make it 'longer' or shorter once fitted

Can't see the pics in that how to but FWIW i've seen three different versions, my half facelift '93 320te had the early style aluminium turtleshell cover with the later one piece rubber trim and a different number of screws holding the turtleshell on compared to the early versions i've rebuilt. Like JC220 i 'upgraded' mine to the clip on plastic cover so i don't have to pull the entire thing to pieces to lube the eccentric portion of the linkage

 

[brucemillar]

Any news?

If of any help. 3 in 1 white aerosol lithium grease is good here. It comes out the can under high pressure (my greasy head, hair & face can testify to this). Using the straw it gets into those hard to reach parts.

Sent from my iPhone using sausage fingers.

 

[Boltneck]

The wiper isn't hitting any of the trim around the screen and the wiper blade is the correct length purchased from Mercedes Benz. If you watch the water marks on the screen as the blade sweeps back you can see where the blade rubber flips over from leading edge to trailing edge about 5 inches from the park position and it makes a "thwump" sound each time it does this. It only does it when there's sufficient rain water hitting the screen as I suspect as the screen gets dry there is more friction on the blade rubber and it flips over as it changes sweep direction on the passenger side. I cleaned and lubricated the mechanism a few months ago so no issues there. I have found that by twisting the arm slightly to make sure it is parallel to the screen I have changed​ where the wiper blade flops over to its trailing edge. I can still hear the blade flop over but it is no longer in my field of vision so slightly less annoying.

 

[Dec]

It doesn’t seem to be wiping the section between the Yellow lines on the outbound sweep, best seen with the video in slow motion, see... https://pasteboard.co/cecGOavmz.png

A video as seen from the outside would be a lot better than from the inside.

Dec