The
http://mb.braingears.com/ does not even show a 1985 300D W123 or
W126 cars so that WebSite will not be of help.
What's your car. For such a simple task, I think the instructions for a close model should work. Post the specific Yr/Model/W123 etc and then if you want me to e-mail you the file, just e-mail me via this FORUM.
Sam Ross // Novato, CA