So, this could be a weird one. My fuel gauge on my 1970 Pontiac LeMans is stuck on full, and I found the issue.

I did replace the fuel sending unit, and it worked for a little bit, but then broke almost immediately. When I took the fuel tank off again (annoying to do btw), I saw a big metal plate that came loose inside the tank and was hitting the fuel float, pushing it all the way up. I think this metal plate might be some kind of slosh guard?

Can the fuel tank be repaired? I tried slamming the plate back into place with a pry bar but it came loose again. Can it be welded? Do I just need to buy a new tank? I believe it's an 18-20GA tank with 3 vents.

Side note, the car is back on the road as of yesterday. I had the transmission rebuilt (TH350) and rebuilt the entire rear suspension. It's been in the garage since December and it's like a whole new car.

The good news is yes the tank can be repaired. A competent gas tank repair shop can clean and repair the tank.

The trade off is cost. A new replacement tank is just under $200. So what will a repair shop charge you vs the cost of a new one?

That decision is left to you and your wallet.

13 hours ago, Frosty said:

The good news is yes the tank can be repaired. A competent gas tank repair shop can clean and repair the tank.

The trade off is cost. A new replacement tank is just under $200. So what will a repair shop charge you vs the cost of a new one?

That decision is left to you and your wallet.

Hm ok. I'll call around and see how much it would cost to get it repaired. 

Let us know what you decide to do. Did anyone mention how we love pics around here?

they are going to have to cut it open to fix that ...

new tank sounds cheaper ! and wont have cut marks where it was opened and potental leaks from the rewelding 

Get a new tank from Tanks, Inc. And definitely preserve that build sheet paper on top of the tank!! What a find!!

https://www.tanksinc.com/index.cfm/page/ptype=results/category_id=128/mode=cat/cat128.htm

These are all tanks for fuel injected engines but call them up and see what they have - there is likely a cap for where the FI pump would mount.  Take a few measurements of your current tank and the space available under the trunk floor before you call.  I had to use a two-gallon-larger tank meant for a 65-66 Chevrolet Biscayne (their TM37C-T model) in my 70 Catalina. But it fits very nicely.

Rick

A lot of the online catslogs have OER replacement tanks for non-EFI cars too. Cost is the most important issue here.

UPDATE:

I fixed it myself, whether it stays or not and whether it leaks or not is still to be seen.

I looked inside with a bore scope, and saw where the welds failed. I then pushed it back into place.

Then I drilled 4 holes in the top, through the baffle as well. I used sheet metal screws on two of them, and rivets on the other two, then covered them in black RTV.

I haven't filled the tank all the way back up yet, but the fuel gauge is now where it should be.

Fuel gauge is fixed, the baffle hasn't broken loose after filling the tank up and driving it a lot. And I haven't seen any leaks. Although it is kind of sad watching the fuel gauge drop in real time while driving...

2 hours ago, Dom L said:

Fuel gauge is fixed, the baffle hasn't broken loose after filling the tank up and driving it a lot. And I haven't seen any leaks. Although it is kind of sad watching the fuel gauge drop in real time while driving...

It’s our duty to burn up all the fossil fuel Dom
so the next generation don’t have to worry about it