Mystery Fuel Leak?

[bobswei]

On my '74, I've had the gas tank out a few times. I've replaced fuel lines, new clamps and it's fine, if I only add about $10 in fuel. If I add $20, I get a fuel leak. It's leaking and getting inside the car by the peddle cluster and also drips out the bottom by the MC. I first thought it was the hose clamps, so I added sealer and an extra clamp. Now, I thought the leak was inside the tunnel, (crack or hole in metal line). I don't see any evidence of that. Now, I'm back to the hoses and clamps. But how can it get from the access hole under the tank, to inside the car? Also, it smells of gas much worse in the car than in the trunk. I put a catch container under the car one evening and in the morning I had maybe 1 or 2 gallons in it.
What's going on??? Thanks for any ideas.

[Dave at Pelican Parts]

Check for rust holes, especially on the parts of the tank that rest on the carpet pieces you have. These can hold water and dirt, and can abrade/rust pin-holes in the tank. The original felt pads could do the same, BTW.

The symptoms of only leaking when there is enough fuel in the tank match with holes being further up than the bottom of the tank.

--DD

[bobswei]

Dave, you're a genius. I've had the tank out, resprayed it a few years back and I thought it was solid. I woke up at 4 this morning trying to figure out how the gas got to a different area. This morning, after seeing your response, I put soapy water in this area and added air into the tank. Yes, bubbles!!! Just where you said. A tiny pin hole. I sanded the area and found a bigger hole. Sanded, cleaned and put on some gas tank approved JB whatever so will reinstall tomorrow.
Thanks for the great response. Bob

[808 WRX]

Might be a good time to add stainless fuel lines. Black Friday sale at tangerine racing, free shipping on fuel lines.

[Tobra]

I need to get those fuel lines myself

You want to make sure the lines to the charcoal filter and the seal on the gas cap are good too. That is where my fuel smell came from. Gas cap was only an issue with a full tank on a windy road. Took a minute to figure that one out.

[bowlsby]

As pitted as that tank looks, its a good candidate for replacement.

[Cairo94507]

I agree with Jeff; replace that tank and if you do not have the SS lines from Tangerine Racing, now is a great time to replace and eliminate a potential fire.