I haven't really dug into the rear brakes except for cylinders overhaul and bleeding.
Have a look at these videos to get the idea of the way this type of brake shoe self-adjustment works.
There have been some changes on the pin design for the friction assemblies but the idea remains .



https://www.youtube.com/watch?v=-0ZIN7gG-7U

https://www.youtube.com/watch?v=s20pLwIBNHM

https://www.youtube.com/watch?v=WDRB0Udo-AY

Do the two persons brake bleeding procedure before dealing with the rear brakes.


You can start a new thread in the Vintage subforum .

Make sure you find some literature too. Look for the "Early Model Years" vol.3 that MBUSA issued some years ago...also check for Chilton's manual covering the 60-ies MB's.

Just in case...can you confirm this is the MC (A0014306301):

https://www.pelicanparts.com/More_Info/0014306301.htm?pn=001-430-63-01-M4&bc=c&SVSVSI=2247