There is a second part online now https://www.youtube.com/watch?v=rwOEqa121Aw
It's nice content but I can already see issues.
1) Hydraulic door switch on front left window has a worn aluminum lever (oval hole). He just adjusted the screws. WRONG! The lever should be replaced soon. See picture from my car
2) There is definitely a pressure port leak on the front left window that he is ignoring. The oil spill is already visible on the door insulation.
I think this is exactly how these cars hydraulic system should not be maintained. I'm pretty sure that more levers need replacement. Almost all pressure port seal are dead a leaking.
PS: Keeping Aeroshell Fluid 4/41 as intellectual property is the nice joke :-)
600 #796 (1967 US version)
300SEL 6.3 #1285 (1969 EURO version)
300SEL 6.3 #5346 (1971 US version project)