collapsing gas tank C3

[Terry M.]

Re: collapsing gas tank C3

I think we had this discussion once before. My original 1970 gas cap has a rubber seal -- and it says SEALED on it. I've got one of those valves on the gas tank also. I'm hoping it keeps working -- both pressure and vacuum. And when I open the cap after the car has been running a while -- there is that wosh of air that some refer to. Happens on all my other cars too -- up to and including the 2001.

[Joe L.]

Re: collapsing gas tank C3

Terry------

The pressure vacuum valves or the vented-type caps do not relieve so as to maintain abient pressure at all times. In fact, they allow there to be significant pressure build-up in the tank since this pressure is helpful in preventing vapor lock. However, I do not know at what vacuum the valves release and allow air into the tank.

Generally, the problem with these pressure/vacuum valves is that they start to leak.

[Terry M.]

Re: collapsing gas tank C3

As in leak fuel, or leak air?

[Terry F.]

Re: collapsing gas tank C3

I agree! I usually contemplate things a good while before trying something like that. Making comments on the board, you sort of jump to the first thought that crosses your mind.

I learned a long time ago that getting all the flamable vapor out of a tank is practically impossible. I think leaving it out in the hot sun for a couple years might do it but it would probably do other things to it too.

Agree, water would be better. Terry

[Dennis D.]

Re: collapsing gas tank C3

Joe

Been so long ago that it may have been what you suggest. I DO KNOW the rubber didn't work, and I couldn't get the original type. Have to check now what is was.

Funny how your dating goes up to, and around 1970. I find that to be the case all too often.

[Joe L.]

Re: collapsing gas tank C3

Terry------

Fuel. As a matter of fact, minor leakage from the valve is what destroys a lot of build sheets. "Later in life", the valve starts leaking more fuel. Then, the fuel odor may be more noticeable in the car.

[Joe L.]

Re: collapsing gas tank C3

Dennis-----

I was pretty sure that the 70-only cap used a rubber gasket. Terry confirms that in his post.

[Mike Baker]

Re: collapsing gas tank C3

When I read your post I remembered my Dad using water pressure to test a tank he was going to use for an air compressor.

That was probably in the late 70's. Funny the things you remember.

[Terry F.]

Re: collapsing gas tank C3

True...

I associate so much with my corvette or just working on it. I think I will work on it tomorrow

Terry