goatjacket

Been troubleshooting a fuel leak on my 68 and would like some help before going further. Noticed fuel dripping on passenger muffler after driving in town, spirited driving or not didn't make a difference. I would see drip marks on top of the muffler and lines that come out the bumper bolt hole. Howver, no fuel leaks, or at least not noticeable when idling. Looked at rubber hose from sending unit on bottom of tank (it's a big block car/tank) to hard fuel line on passenger frame. No noticeable cracks or even moisture. Tried taping just to see what happened. Still leaking gas but don't really see the hose wet.
Planning on draining tank and it seemed as tank went below 1/2 the leaking stopped. Filled it up again and it's back. Color me confused now. Is it possible the hose has a tiny split or crack that only expands as pressure raises from the pump? But what about no leaking under 1/2 tank? The tank is dry, just lower frame right above passenger muffler has drips but don't see it dripping down from top. In my head the gas is flowing from hard line connection down the frame rail landing on the exhaust. Any thoughts? Just filled the tank so looking for thoughts before draining to replace sending unit hose.

azza2u

Does the tank thats in there have the extra nipple on the top passenger side for a fuel return hose? Mine does even though my return line is not connected so I've had to cap it so it doesn't leak when the tanks over half full and the gas sloshes onto it.

goatjacket

I haven't pulled the splash fill boot off to see but can check. Would it be close to the fill neck? Yesterday it seemed to leak more when making a turn (I could see the drip trail compared to straight driving).

Revi

If your car still has the original gas tank installed, it may have a hole (or pin holes) rusted through it. The rust hole can be on the topside of the tank, only spilling when the gas is sloshing around. Dropping the fuel tank isn't that bad of a job.

goatjacket

The tank was sealed a few years back so I don't expect any rust issues, but anyhting is possible right?

bashcraft

How was it coated? Inside? Outside? Over top of rust?

azza2u

This was the tank out of my 68 when I replaced it. Apart from pinhole leaks in the base, the gasket on the filler neck had perished allowing gas out, as had the hose on the nipple for the fuel return with was allowing gas to slosh out like you are describing.

goatjacket

Thanks for the picture! I honestly had no idea there could be a return hose that high. I'll crawl under the wheel well to see if I can get eyes on that return line. It's the original tank so perhaps that return line is a problem if there. It seems it would be the right location.

goatjacket

OK, need a little history or toughts on my car status. Thanks to the picture, i confirmed the return hose was actually missing on the top passenger side of the tank. That clearly explains the leaking when full and even more when turning. I feel silly for such an easy problem. but now that I have it identified, the question is how to fix. According to my assembly manual, that hose goes to the fuel return...I don't have a fuel return. OK, now what? First question is why don't I have a fuel return line next to the supply? For simple solutions, can i simply attach a 3/8' hose and cap it?

goatjacket

Disregard all, a little more searching I found my answer below. Thanks to the 2003 call-back from Chuck if you're still around the forums. Never had real doubts, but I love the treasure hunt of confirming my car was a Tri-power even if you don't match the numbers. Another win for the forums! I'll put a cap and consider the case closed.

"If you look at 68 and 69 cars, on originally equipped Rochester cars, you'll see what appears to be TWO fuel lines running along the frame rail, and up to the vicinity of the fuel pump. The larger is the gas line, the smaller is the return line. Why? I honestly don't know. I seem to remember that it had something to do with preventing vapor lock with the Rochester carb. I'll
bet your car has two lines.

Tripower cars have only ONE line running along the frame rail, and that's the fuel line.

That's one of the "tricks" for spotting an original Tripower car in 68 and 69. Remember that BOTH style tanks use the vented fuel cap. Chuck"