When I park my 67 Lark on an incline gas leaks past the filler cap. Is there a special gas cap we should use on these tanks? If so who sales it?
From what you've said I would ask the following question; When exactly does this happen, day or night, that is the temp outside? And how much fuel is in the tank? I also think that there are a couple of other section on teh site that are better suited to answer the question. I'd start with a more detailed post on "the bench" and then maybe in the chassis restoration section too.
THe cap should be a Non-Vented, deep cam type cap. Usually they will say non-vented on them. It's common to many cars of the era. Maybe it's a vented cap? Maybe the neck on the tank (if new) was installed wrong? Maybe it's just a worn gasket on the cap. I could not turn my cap shut all the way on the car I recently bought...no way. Bought the right cap, it's like new now!
It only happens when the tank is full. It has to be the cap, even though it is new. This is why I am asking for info on the correct cap, and where to purchase it. Yes this is probubly not the ideal place to add the thread, I though about it after the fact, but I hope that wont be an excuse not to help. This was a cap that was specific for the year of the vehicle. I know it does not completly seal when screwed in place. Should it seal completely when the cap is screwed in place?
It should seal, when you turn it, you should feel it stop and like lock in place with a light clunk. My own cap wouldn't close all the way, it was REALLY hard to turn the last 1/2" or so. The cap is not unique to the car, you can go to a parts store or chain like AutoZone + get one. The right cap is NON-vented, and will probably say that on it. It should turn easily and lock. Maybe 7-9.00 at the store.