Repairing Your Windshield Wiper Assembly

Repairing Your Windshield Wiper Assembly

One would think that every single maintenance and repair subject would have been mentioned, some of them hundreds of times, on the various Mercedes-Benz mailing lists over the last five years or so. I signed onto the Realtime list in 1995, and all the others since that time, and have seen no mention of the subject of my post today.

About two years ago, a friend mit frau were headed off on a weekend trip to the Washington coast for a day on the ocean beach. The weather was poor with heavy rain and as they headed down the Interstate passing through Tacoma (WA) the windshield wiper on their high-mileage '85 190E came to a stop partway in it's travel arc. They stopped on the shoulder and after an unsuccessful attempt to get the thing moving, they drove slowly to the next exit and made their way several miles to the local MB dealer. The diagnosis was a failed wiper motor or wiper transmission. This comes as an assembly and costs about $1000 installed, so they said. So, they rented a car and headed for home, the trip forgotten. Upon retrieving the car later that week, the bill was paid and soon after arriving home the cracked windshield was discovered, just where the technician had struck it with a tool while installing the new part. This was of course denied strongly but eventually the dealer replaced the windshield. All in all, not a good week.

So, while driving my 95 C280 in a similar rainstorm several months ago, and watching the wiper arm slowly groan to a stop, I saw myself going through the same experience. Since I was close to my MB dealer I presented my self and car at the service department for a diagnosis. My service writer (I always deal with the same one, the "Team" concept) felt that the transmission assembly would have to be replaced. Since my extended warranty would cover this I wasn't too concerned until he said that he couldn't work the car in until the following week. So, here I was with a potentially undriveable car and no way to fix it for ten days. I headed for home, between rainstorms, and decided to see what I could do, if anything,

Finally, here is the important part. Looking at the visible part of the wiper assembly, there is a large semi-oval cover about the size of the palm of your hand which the wiper arm emerges from. I wanted to take this cover off but the method was far from obvious. Here is how I did it:

1. Raise the hood for improved access.
2. With the ignition off, rotate the wiper switch to the first position.
3. Turn the ignition on and off rapidly, so as to move the wiper arm out of the park position.
4. Move the arm manually to the straight up position.
5. Remove the three-sided rectangular cover (lower end of arm) that extends over the cap by pulling it straight up from the bottom end.
6. Using a sensitive fingertip or a dental mirror, locate the two small recessed rectangular openings on the underside of the cap at roughly the 5 and 7 o'clock positions.
7. Using a tool with a 90 deg end such as a dental pick or a small allen wrench, release the catches in the access holes while pulling the cap upward with the left hand.
8. Now that the entire articulated wiper actuator is in plain view, you will see as I did that the shaft that extends the arm up into the windshield corners (twice per sweep) is very likely no longer lubricated.
9. Remove all the old grease from the shaft and bushing using for example a cloth soaked with lacquer thinner or similar, moving the arm back and forth to expose the arm surfaces inside the bushing.
10. Apply new lubricant and I don't mean WD-40. I used Sil-Glyde, a silicone grease which has a working temp range of -20 to +400 deg F.
12. Reassemble in reverse order.
13. Congratulate yourself for saving about $1000.

As to the position of the release catches, the two cars I have checked are my own C280 plus a '99 CLK430 (the replacement for the aforementioned '85 190E) which were identical

My car's wiper problem is entirely gone and after two months is still operating normally.

I subsequently asked two service writers plus the service manager at my dealer if this little operation is ever done as part of a scheduled service, especially at high mileages. The answer was no, never. I expressed some surprise. I do see that selling an expensive repair is a whole lot more profitable than applying a little bit of grease.

I also spoke last week to the two local MBUSA reps about this little adventure. When I told them how I had resolved the problem there were honestly interested and promised to follow up with perhaps a service recommendation.

Since nearly every MB passenger car built in the last 15 years uses the single arm wiper, I now expect all of you with cars so equipped to head on down to the car and perform this little maintenance job, thus derailing the sale of countless wiper motor assemblies.

Roger Elingson

Ref: Frank Mallory's database and