If I remember right you have a 1400 series machine. If this is so, there are no orings. You either have cracked fittings or the balls on the end of the lines are burred. In either case, we always had to replace the defective part(s).
I agree. My 1680's bleed line from the motor just cracked this year. No replacment to be found, so I ground a very fine point on the tig electrode and filed the crack with a sharp file, then welded it back together with some very fine filler rod and filed it smoothe enough to get the fitting support sleeve to fit. It's still working, but I plan to replace it with a hose soon.