I don't know about that particular model, but the Prontor Press shutters I've owned had gummed up shutter blades. It was pretty easy to clean them by opening the back and taking them out to clean. It is easiest to replace the blades when the shutter is in the closed position, and the "extra" blade goes on top of the first one you put in after putting the rest in clockwise.

Quote Originally Posted by wombat2go View Post
The term petrol and gasoline in a 1957 translation from Gauthier's German manual surely refers to the automotive fuels. the English term was "white spirit" otherwise.
At that time, petrol (as I recall, both grades) contained tetra-ethyl-lead plus other additives including upper cylinder lubricants.
I grew up in my father's auto dealership/workshop and to clean things including small parts they used half/half petrol/kerosine in a high air pressure spray gun.
Flammable and a health hazard (although those guys lived long ! ) it sure got the parts clean and probably left some lube on the surface.

I haven't opened the Prontor SVS here but from what I can see it is not up to the quality of the Graflex Wollensak ones here.