Sunroof actually slides on little rubber/felt "Feet" that are lubricated by a
Mysterious substance "Gleitepaste"...Unlubed the felt wears away,along
with the rubber.Then the arms drag on the Stain-less "Rails".
Or Might be the angle lifts broken
Or might be dry cable.
SunRoofs are looked upon as VooDoo by many Owners and some Techs...
With good reason...unprepared and/or not-very-expert...These things can
"Drag You Down to the Vault" like some Nasty Old Alligator.
'Rarely,a novice (Almost a Savant) will delve into the SunRoof ...Fix It
and Declare the rest of a us all a bunch of Nervous Nellies.
('Makes You crazy)
However,'Seems you are a Stout Young Person of Good Heart...
Let the "Search" and "Advanced Search" (sort of Google for the Forum)
buttons become your new best friends.(Days and Days of Info there)
AND, YOU Will WANT TO SAVE THE NEXT LINKS,
IF NOT DOWNLOAD THE ACTUAL INFORMATION.
PD's user friendly Service Manual:
http://www.pauldrayton.com/uploadfiles/merc/Service/W124/Index/104index.html
Mercedes Benz Club of Russia's ILLUSTRATED Electronic Parts Manual:
http://www.detali.ru/cat/oem_mb1.asp?TP=1&F=124032
With the sunroof page for your model: (Pick from the lower choices, B M )
http://www.detali.ru/cat/oem_mb1.asp?TP=1&F=124032&M=104.992&GA=722.369503&GM=717.450&CT=F&Cat=44Q&SID=78
The Modern American Bible of W124 by member GSXR:
http://www.w124performance.com/images/