'91 300SL R129 slow windshield wiper

[Benz Mondi]

Judging from my recent posts, one can tell that I'm slowly getting to all the issues that came with my car when I purchased it 1 month ago. Fortunately, my MB Indy of 10 years and all my MB's, thinks that despite the little issues that I can fix myself, it's a solid car.

My windshield wiper speed is way too slow and sometimes hesitates as it sweeps across. Even with the wiper arm removed it's much slower than normal.

Doing the a forum search, I found some posts about relay issues, as well as, motor issues.

Which is the likely culprit?

Am I correct to assume that I can also replace the mono-blade wiper motor with the one's from the W124's?

Thanks,

AL

[tecqboy]

The most likely culprit is that the lube has dried up on the actuator mechanics. Cleaning the hardened grease and re-lubing will most likely get things speeded up. There are disassembly and lubing instructions elsewhere in the forum. The same mono wiper was used in oh so many MB's.

[Benz Mondi]

Originally Posted by tecqboy

The most likely culprit is that the lube has dried up on the actuator mechanics. Cleaning the hardened grease and re-lubing will most likely get things speeded up. There are disassembly and lubing instructions elsewhere in the forum. The same mono wiper was used in oh so many MB's.

Excellent tip. I don't know why I had forgotten a youtube vid on the exact same tip http://youtu.be/W3IPjKgC5AQ(clean and lube with Synth grease) and the replacement http://youtu.be/ewhuU2no1tU

I went ahead and took everything apart and did find the grease was more like tacky glue than lubricant. I picked all the old grease I could get to, cleaned up with WD-40 and then used bearing grease I already had. Put everything together and... improved the action by 50%! It's still is not the same speed as designed, but will suffice until I get a new motor replacement. Should be all and well after that.

Major Tip: Once you get the motor and wiper assembly out of the car and on your bench, BEFORE you loosen one nut , make sure you not only take detailed pictures, but also mark identifiable points along the whole assembly. You'll need to return everything to the same alignment or you'll be sorry. There is a precise ballet of how all the parts in the action are timed. Disrupt that timing and you'll find yourself re-installing everything more than a couple of times more. My pictures weren't up to the task so it took me 4 times before I figured out the precise alignment.

I'm from the "if I have to touch it, then I might as well clean it also" school of DIY'ers so it took me longer. However, now it all looks great.

Thanks.

[Chris at Pelican Parts]

Glad to hear you got it worked out! My wiper has been performing flawlessly during our recent LA deluge so I (thankfully) haven't had to touch it yet.

Just for your research purposes in the future, we do have a collection of tech articles on the R129 that could help answer some questions before you dive in: Mercedes Benz R129 Technical Articles - Pelican Parts

-Chris