PeachParts Mercedes-Benz Forum - View Single Post

JimSmith · #13 03-12-2002, 11:14 PM

Sean300D and D Norton,

The cable is connected to the sunroof in the area hidden by the sunroof liner. The way you get the cable out is by breaking this connection and running the sunroof as far as it goes in the closing direction, then, once it disengages from the motor drive mechanism you pull it out of the guide tube with your hands. To replace the cable, you do the reverse; you feed the cable in by hand as far as it goes, then use the motor to "open" the roof and draw the cable into the guide tube.

If the cable makes a clunking or scratching noise when you try to operate the roof, it is an indication that the cable to sunroof panel connection is failing or failed. Noises from a failed drive mechanism in the trunk are not likely to sound the same as the cable and its connection to the roof mechanical equipment failing at the rear of the roof panel.

I just went through this with my son on my (now my son's) 1986 190E 2.3-16 that has a simple, non-tilting, electrically operated sunroof. On this vehicle, the connection is via a stamped, galvanized sheetmetal clip that wraps around the "head" feature on the end of the cable to capture the cable, and by two screws that go through two holes in the clip on either side of the cable that connect to the cross beam at the rear of the sliding steel panel. The failure I experienced presented itself when I tried to open the roof, I heard some noises that sounded like whipping of the cable a little, and some metallic clanking, in the roof area at the rear of the steel sliding roof panel.

When I took the liner off, it was relatively easy. It went back on, and other than a good cleaning that it got while it was out, it looks exactly like it did before it came out.

The problem I had was clearly revealed when the liner came out. One of the screws that held the clip to the mechanical operating lever (a cross beam at the back of the sliding steel roof panel) had come out. This allowed the cable, as it goes through the last bit of designed travel which lifts the rear of the panel and locks it in position, to extend a little further and twist around, as the clip rotated around the pivot point created by only having one fastener left. It also bent the clip so it would not feed back into the slot on the bottom of the cable guide tube. All this is hard to describe in words, but get the liner off and it is readily apparent.

Ultimately, the cable came out far enough to become disengaged from the motor drive mechanism in the trunk and it would no longer do much when you tried to open or close the roof. All you would get was a very audible sound of the motor running and some light clicking that came from the trunk and not the roof area.

Changing the clip cost $0.38 and took about an hour once my son and I had the new part (clip) and knew how the system was supposed to work. The cable guide tube, with the slot in the bottom was the hardest thing to figure out as the clip was so bent up the concept of it sticking out of the slot was not that apparent to me or my son.

So, the reason to take the roof liner off the sliding steel panel is to figure out if you will be spending $6-700 or even $800 to fix the problem or $0.38 for a clip and a few more pennies for a new screw if you can't find the one that fell out.

And, I later determined the best way to get the liner out is to pry the screw clips loose at the front edge, and once it is free push it back into the roof far enough to see the cross beam, cable and clip connection. Unscrew the clip and free the cable, then manually push the cross beam rearward so the roof panel drops. Then slide the steel panel rearward. Once the roof is open, you can pull the liner back forward, past the front edge of the sliding steel panel and then feed it out of the roof opening without any damage. Putting liner back is the reverse.

All this applies precisely to a simple, electrically powered sliding roof arrangement on a 190E. It may not appy exactly to a 1981 300D. However, my past experience with Mercedes is that they are very likely to reuse the same arrangement that has been proven on a previous chassis unless they add some feature that requires a change. So, I seriously doubt it all applies directly to a roof with the tilting up feature which is common on later 190E's and other newer models. I suspect it does apply to the W123 chassis cars as they did not have the pop up/tilt feature.

Good Luck, Jim