I filled my newly-purchased 76 TT with gas last weekend and took it around the neighborhood this morning to run it a bit. When I got back to the house after 10 minutes of driving, I noticed gas dripping from the bumper connection point at the right rear. I couldn't find the source of the leak, but it was definitely coming from somewhere on the fuel tank. The leak wasn't fast, about one drip every two seconds, and it lasted for 20 minutes or so, then quit. This is the first time that this has happened, as far as I know.

What puzzles me is that I didn't see any leaking during the week while the car was parked, although I did notice a gas smell when I had it in the garage. Is there a vent tube on the fuel tank that has been disconnected or something like that? Or is this a symptom of a tank leak in a specific area? Bubba gouged up the fuel filler neck so that he could add leaded gas when that was still sold, so I wouldn't put anything past him!

 

One thing to look for is the sending unit leaking. The unit uses a cam lock feature to lock into the tank. There is an o-ring between the two pieces. Mine has been leaking there off and on for a while. I have replaced the o-ring without much improvement. What I had to do was massage the tabs and cams to increase the amount of compression on the o-ring. All this is much easier done with the spare tire carrier removed. Taking that off will let you see all the connections and possible leak points.

Ken

 

There is a cork gasket between the filler neck and tank which generally turn to dust, Check that.

 

Mine too.
I can see a vent tube running off to the side.
When I fill er up it will also drip drip drip onto the RR muffler
I can see the tube up there.

I need to extend the tube down past the muffler, I Guess
Can't find illustrations on fuel tank diagrams to know any better

 

This sounds obvious - but get to the bottom of that leak before driving it anymore - don't need any fire stories here!

 

I had the same problem with my 76. There are two rubber lines at the top of the fuel tank that crack over time. Drop the fuel tank and inspect those lines. They connect to two metal lines that run along the inside of the right frame rail. Its pretty easy to change the rubber lines with the tank down. I had a slow leak coming from near the fuel tank. Couldn't tell where. I soon as I dropped the tank, it was pretty obvious.

 

I had been thinking that it might have been caused by these lines. Is there any way to get to them without dropping the tank?

 

No, not really. Up to '74 they were easy as the sending units were at the bottom of the tank, so were these rubber fuel line connections. 1975-'82s had top fuel tank connections & also '75-'77s had a "safety shield" over the tank which made it harder yet to get to the lines exiting the top of the tank. You may get away with "lowering" it a few inches to get to everything, which includes lowering your passenger side muffler also to allow access to this area.