2019-12-10 maintenance manual for Mercedes T1 601 Bus with OM617 engine
Since 2012 and I do all of the regular maintenance by myself using this guide which is constantly upgraded over the years.

Of course I had to do some more repair jobs on the car. Since its more
than 30 years old now, this is normal. The next major operation will be a
transmission diagnosis, since the gear shifter is quite stiff to use.
Also the front window is leaking, a common problem with this model.
To address this, the windshield has to be removed and the frame needs
some rust repair. I probably need to develop some welding skills to do
this...