WIS 77.20 Electric Sliding Roof
Issues
Does your sunroof hesitate to open? Does it make a "grinding" noise, and slows down at certain parts while opening/closing? Do you have to push it sometimes just so it can close all the way? If it is loud, slow, or just not working right, these DIYs are for you!
Sunroof Lining
Excellent BenzWorld Member G-AMG style Photo DIY How to Remove Sunroof Liner.
http://www.benzworld.org/forums/w140-s-class/1448445-photo-diy-removing-sunroof-liner.html
Sunroof Restoration Repair Service Dismantle
Excellent article by BenzWorld Member MafiaDON Sun Roof Restoration Repair Service Dismantle.
Summary
This DIY document refers to a write up on how to RESTORE your sunroof to BRAND NEW condition! Literally. (This write up is exclusively for W140`s, but it may also apply to other models.) Best part is, the whole restoration will only cost you $10. Follow the steps exactly and you will be 100% satisfied with the results.
http://www.benzworld.org/forums/w140-s-class/1610502-diy-w140-sun-roof-resotoration-repair.html
Sunroof Sensor
Summary
Problem with the sunroof opening the way it should but stopping and reopening when you try to use the auto shut, then this is for you. I have a Mercedes repair guy that comes out to my house to do repairs if needed. I was having that same issue; he said that all it was is an adjustment needed to the sensor that adjusts for wear; which he said was very, very common. He hooked his computer up and had it fixed in about 30 seconds! He didn't even charge me! It was not anything bent or broken within the sunroof!
Sunroof Drains
Summary
It is possible for the two drains that run through the "A" pillars to become clogged, and back up. It is also possible for the rubber hose that runs through the "A" pillar to become disconnected from the lower part of the drain.
You could try reaming the drain or blowing it out. If the rubber hose is disconnected, it is reachable by removing the interior cover of the "A" pillar.