Locking Gas Cap

[Patrick H.]

Re: Locking Gas Cap

Install the locking cap in these situations and the standard cap while driving. I do it religiously.

You mean did.

[Joe L.]

Re: Locking Gas Cap

You mean did.

Patrick-------


I was afraid someone might think of that. But, I'll be doing it again. When? That I'm not sure of.

[Patrick H.]

Re: Locking Gas Cap

Patrick-------


I was afraid someone might think of that. But, I'll be doing it again. When? That I'm not sure of.

Or I will.

[Mike F.]

Re: Locking Gas Cap

I will take it.

George Linares
418 W. Chestnut St.
Hoopeston, IL 60942

Thanks,
George

You got it.

[Steve L.]

Re: Locking Gas Cap

I do not recommend the use of these caps "on the road" as they usually leak gasoline.

Been using this cap all the time since 73, never noticed gas leaking. Maybe I just got a good one?

[Joe L.]

Re: Locking Gas Cap

Been using this cap all the time since 73, never noticed gas leaking. Maybe I just got a good one?

Steve------


I used several different ones, all new when I installed them. I never had one that didn't leak. Everyone else I can recall talking to that had used them said the same thing. The 63-69 models also leak through the vent hole. It's just a hole with no valve. Basically, it's the same venting system that GM used for Corvettes in 1963. That didn't last long for the same reason.

I've used the 70-74 type, too, as my late 1969 was built with a tank with the integral pressure/vacuum valve and does not require a vented cap (although one was originally installed). In fact, I thought this was going to solve my leakage problem with the locking cap. It didn't.

Liquid gasoline is not the only leakage problem. The main problem is that gasoline VAPORS escape and waft into the cabin.

[Steve L.]

Re: Locking Gas Cap

Where does it leak from? Is it apparent by smelling gas when walking at the rear? Can you see traces of gas residue on the boot or the cap itself?

[Mike E.]

Re: Locking Gas Cap

My 72 had a locking cap on it for years. There is an inordinate amount of rust on the narrow "ledge" on the inner circumference of the fuel filler neck. It's clear that the cap, which didn't/wouldn't fit tightly, not only allowed gas out, but water residue in.

[Joe L.]

Re: Locking Gas Cap

Where does it leak from? Is it apparent by smelling gas when walking at the rear? Can you see traces of gas residue on the boot or the cap itself?

Steve-------


In the case of the 70-74 locking cap, it leaks from the interface between the cap seal and the top edge of the filler neck which it seats against. I do recall seeing liquid fuel in the boot and I definitely recall the aroma of gas in the cabin. I do not recall if I ever noticed it when walking in the area of the rear of the car. The 63-69 locking caps leak from the above AND the vent hole.

Why do they leak from the interface between the seal and the filler neck? Well, these locking caps do not feature a CAM LOCK like the standard gas cap. The cam lock ensures a tight seal between the cap's seal and the filler neck, especially with the 69+ neoprene cap gasket. The locking cap uses spring loaded locking bars which are supposed to clip under the lip of the filler neck. This just does not result in a tight seal. I'm amazed that yours seems to have worked for so long.

[Jim T.]

Re: Locking Gas Cap

Been using this cap all the time since 73, never noticed gas leaking. Maybe I just got a good one?

Steve in using the locking gas caps on my 1968 and 1970 I have not noticed any leakage. I have driven my 1970 from Dallas to San Diego, back to Dallas and on to Norfolk, VA in the mid 70's and also never smelled gasoline. Perhaps I was not sloshing the gas in the tanks enough.

[Terry M.]

Re: Locking Gas Cap

I use the locking gas cap on my 1970, except for judging. I bought it in February or March 1970, and it has the vent. It always leaked from both the filler neck and the vent hole during road use until the fuel level dropped. About 2/3 of a tank of race gas evaporated during a decade of storage. I only smelled gas in the garage for one 3 or 4-month span during that decade -- toward the end of the term.

[Robert R.]

Re: Locking Gas Cap

Would a possible "fix" to the problem be as simple as a thicker gasket ?
I suppose one would need to press down on the cap while unlocking it with a thicker gasket installed.

[Steve L.]

Re: Locking Gas Cap

Steve in using the locking gas caps on my 1968 and 1970 I have not noticed any leakage. I have driven my 1970 from Dallas to San Diego, back to Dallas and on to Norfolk, VA in the mid 70's and also never smelled gasoline. Perhaps I was not sloshing the gas in the tanks enough.

I would imagine that the amount of gas in the tank and how spirited you drove would make a big difference.

I drove docile 95% of the time and didn't fill that tank up all the way because the vapor valve would leak with a very full tank. Maybe this is why I never noticed the leaking cap.

[George L.]

Re: Locking Gas Cap

You got it.

Gas cap received today. Thank you very much. Payment will be put in the mail Thursday.

Regards,
George

[Mike F.]

Re: Locking Gas Cap

Gas cap received today. Thank you very much. Payment will be put in the mail Thursday.

Regards,
George

Received payment, thanks!