I searched and found many panoramic sunroof threads. It sure would be nice if there was just one big one! As there is not, it seems best to start a new one, as I did not find any mention of the mystery spring in the others.

We drove the car someplace Saturday morning and it was fine. On the way back, there was wind noice. I found a loose spring about 4" long on the passenger side at the front of the sunroof track area. I removed it, and the roof closes better, with less noice. The roof only opens about 5". Any ideas on the problem? Where does the spring go? Is there a link to diagrams of the mechanism?

I signed up at startek and do not see the spring in the parts diagrams. As far as I know, the service manuals are very expensive, so I don't have them.

Take a picture of said spring

Here is the spring, with a hollow metal slug inside near one end:

No ideas?

I finally had time to work on it today. The spring goes inside the attachment for the windscreen which pops up when the sunroof is open. There is a plastic cover which fits over it and retains it. That broke. The spring came out, and the square shaft over which the spring is installed stuck up and caught on the front edge of the roof, preventing it from opening fully. I fixed it by using curved needle nose pliers to slide the spring back on the square shaft, then put the assembly down into the channel into which it fits, with the string stopped against some bumps formed on the sides of the channel. I did this with the attachment screw removed. Then I held it all together with the plastic cover over the spring, and installed three small plastic ties wraps to hold it together, with the wrap end connections up. M-B should not have used plastic for the part which failed.

Here are photos to show what and where the repair was made:

There is this procedure to replace this part: https://www.mb-treff.de/tipps-tricks...enge/index.php (in german)

The entire linkage can be replaced. See link.

Just for documentation, I found what was wrong in my panoramic sunroof.
The spring that popped out is a part of the #180 part (as showed before), part number A 203 780 01 75 (left) and A 203 780 02 75 (right).
The last owner did an attempt to fix it, but as you can see in the pictures, it was an awful job and did not work at all.
New parts are the better solution in this case.
Hope it helps.


The broken parts

The washer that holds the arm in the wind deflector

The upper part is right, the lower is missing the washer.

The spring that popped out and kept the sliding roof from opening.

Attempr to fix by the previous owner.

Detail. The metal rod slides thru this plastic piece.

my car is a sl500 convertible.