I got in touch with Axel through a German online community where he and others virtually helped me to deal with the issues I had with my transmission. Axel owns a collection of six classic vehicles. One of them is a nice Mercedes-Benz 307D. He has a huge archive of original repair manuals and has worked on several Mercedes-Benz vans and trucks. On a phone call, he invited me to come by to check out my Mercedes-Benz 209D in more detail. A few days later, we met in a parking lot near Großhau.
Step by step, we examined the technical condition of my camper van. From the back,
all the way to the front.
To my great joy, Axel told me that he hasn’t seen a Mercedes-Benz 209D in such a good condition before. A little rust, but nothing that couldn’t be dealt with easily. 
After treating some minor rusty areas on the bottom of the vehicle, we cleaned and greased the steering knuckles.
We went through the whole engine compartment. I learnt about the functionality of each part, how to identify common issues, and all the tools required to fix them. While Axel showed me everything, I created notes.
At the end of the first day, I had a huge list of common spare parts and tools that I should have onboard to maintain and fix the van on the road.
On the second day, we dove a bit deeper into the parts of my vehicle by studying the part numbers and some manuals.
I learned a ton and gained a new friend in Hürtgenwald! Thank you Axel! 
