I don't think my system is leaking. It cools fine and is not low on refrigerant, but just doesn't have any capacity when the sun is out.
Either way, I doubt that I'd want to get into the habit of topping off an R12 system. That would be more expensive than just fixing the leak in the first place.
What else, '73 MB 280 SEL (Lt Blue)
Daily driver: '84 190D 2.2 5 spd.