I recently did a complete restoration on my '71 Z. I removed the tank and painted it. I reinstalled it with all new hoses and clamps. I filled it up a couple of days ago and it started leaking. I drove it 35 miles and it stopped leaking. It seems to be coming from the driven side and running down the seam and dripping onto the floor. Anyone have any ideas on where this tank is leaking? I have not been under it to see if I can find the leak. Just looking for some info before I started looking.

I tried to fix mine about 8 times now over the last 7 or 8 years. Finally I've convinced myself that it is the seam that is leaking. I'm going to a fuel cell, but I know that the tank liners like the stuff POR 15 sells will seal pinhole and seam leaks. That would be my first suggestion, having tried EVERYTHING else myself...

I sympathize with you though. That is frustrating as hell, especially when you've just installed new hoses and clamps.

It leaked when I drove it back from CA after the purchase. I thought the hoses were rotten so I replaced them all. Now it still leaks when it is FULL. At 7/8, it does not leak. Where the heck? Maybe the neck hose is leaking and draining down onto the seam? Hmmm?

Sounds familiar...posted this today..

http://www.classiczcars.com/forums/showthread.php?t=19836

Yep, that's what mine looked like too. There was no wet gas around the filler on mine though, so you might want to check for that Zsaint. I kept trying to seal that hose on the driver's side there, no luck. I dropped the tank and replaced all the hoses. I changed the hose clamps, etc. I'm fairly convinced that ddezso and I had the same thing going on, and I'm also fairly convinced its a seam leak.

Bite the bullet. Pull the tank out of the car & have a competant radiator/tank repair shop pressure test the tank. You'll know definatively where the leak is. No more wondering/guessing.

From that point you can choose to address the issue in whatever way you wish. Follow Daves "How to..." article and seal it yourself (only), or have the shop fix the leak with solder or weld, then take it home and follow Daves "How to..." or let the shop do the whole enchilada.

I cannot imagine living with a situation like this for 7 or 8 years, or trying to fix it multiple times.

Well I didn't park in a garage, and it didn't leak that much. It wasn't too big a deal, just an annoyance more than anything. You're right though, it was pretty ridiculous to put up with it for that long.

Believe me - that is in my plans. Just waiting for the time and resources to tackle that one...

These tanks are a pain in the A$$ after 25 years or more. I wish there was a way we could have them made under 500 smacksers. I wasn't leaking but My pickup and return lines were clogged. I had posted a tread on red-kote tank liner here

http://classiczcars.com/forums/showthread.php?t=19514&highlight=gas+tank

after all the work I did on this tank I still had to take it out and to get new lines welded in place. The bast thing to do is just like montoya_fan01 said take it to the radiator shop and have it tested and repaired. I did get my problem fixed on my tank and I wish all of you the same luck.

Me too. I bought another tank and it is at the radiator shop right now once it is boiled and tested I will seal it with POR also.. The original was leaking out of the bottom about an inch forward of the drain plug. I hit something on the freeway fell off of a semi. Just glad it didn't come through the floor boards or impail the tank.

check out my write up on por15'ing the outside and inside of the tank, and some sensible mods as well....

http://www.classiczcars.com/forums/showthread.php?t=19034

My tank was not rusted as was the car. Someone had put regular hoses on it over the years. I cleaned the tank and painted it and re-plated all of the hardware. I replaced every hose with fuel or transmission line/hose. I replaced all of the clamps. I used a fuel-sealer under the hose connections to make certain they did not leak. I spent a lot of time making certain the tank would no longer seep. It still does! I am guessing it may be the gauge connection. I did not replace this gauge or the gasket. I will start there.