Beyond the complex mechanics, the manual guides the user through the mundane but essential aspects of maintenance. It outlines service schedules, known as "Assyst," which dictate oil changes and inspection intervals based on usage. It also covers bodywork and interior trim removal, which is essential for the vast number of campervan converters who utilize the W639 chassis. Detailed exploded-view diagrams show the hidden clips and fasteners that secure interior panels, preventing the costly damage that often occurs when attempting to disassemble the cabin without knowledge of the underlying architecture.
: For professional repair, use a genuine Mercedes WIS PDF dump (circa 2012–2014) or an all-makes subscription like ALLDATA or AutoData . For DIY, a high-resolution scanned copy of the Mercedes “W639 Service Information” (3,500+ pages) is essential. w639 workshop manual