Gas Tank Leak

[kustomkyle]

I have a 1986 Regal, and the gas tank leaks from the top when it is full. It isn't a stream or anything, but the surface rust on the tank gets wet spots visible on the back above the seam in the middle of the tank. The tank itself is better than any I've seen on any G-bodies in junkyards (usually they are patched with bolts), it just has surface rust. I'm wondering if there is unseen rust on top or possibly a rubber line is bad. I'm not familiar with the line setup that is on top of these tanks. Could a hose be dry-rotted?

I don't think that I have any other problems from the leak other than the leak itself. The car used to stall when I put it into drive after filling up with gas though. It did it about once a month a little while ago. It hasn't done it yet this year though. I guess something like that would mean the tank isn't pressurized?

I know that if I drop the tank I could probably find out what the problem is for sure, but I drive the car daily, and running the tank low enough so I could drop it would probably cause sediment to clog the filter up. I'm just wondering if there is a common problem that occurs with these cars that can easily be fixed or if I should be prepared to replace the tank.

 

[megaladon6]

it sounds like the sending unit o-ring, the s-unit itself or the top of the tank is rusted. remember, crap gets stuck up there and rots the top faster than the rest of the tank.
stalling right after a fillup is usually the sediment getting stirred up and clogging the "sock".

 

[srercrcr]

My experience for the same problem was the fiber gas lines crack after many years, never had an o-ring go bad. Run the gas down low, undo the straps and let the tank down slowly with a jack and a 2x6 supporting it.