You can get the 126 vacuum schematics gratis from MB here:

www.startekinfo.com

Click on "Workshop resources" in the left column
Then go to page 2
Select "Model 126 Service Library"
Run the online version of the CD and go to your model/year
Pull down the PDF for the vacuum diagram.

MB has made a gift of the complete service libraries ("CDs") for all of the youngtimer cars, via this web site.

Cheers,
Gerry