My old Retina IIIc's shutter seems to stick a bit on the slow speeds (it's been in storage for several years). My guess is that the shutter needs a cleaning and lubrication. Can anyone advise me as to how to get the shutter open without major disassembly of the camera? Is it best to simply flood the shutter with lighter fluid and then oil the escapement?
Also, I've noticed that the rangefinder shows "hysteresis" when I focus (the double image moves more slowly than the focus action but always catches up after a second or two). Again, it's probably gummed up from lack of use. Any suggestions?
Due to the removable front lens element the shutter of the Retina is quite easy to access. I think you might some notes on the Synchro Compur shutter on Dan Mitchell's site:
www.daniel.mitchell.name
On the Retinas it happens pretty often that dissolved lubricant from the escapement gets on the blades during cleaning and the blades will get gummed up, too. Disassembly of the shutter is not very easy but I had good results with thorough cleaning of the blades from the front. But this takes patience.
The rangefinder problem is pretty common, too. Remove the top cover (and leave the camera upright, there are two loose parts of the advance mechanism which might fall off) and clean/lubricate the bearings and the actuating shaft of the rangefinder. You can clean the viewfinder as far as possible but usually they do not become much brighter.