What is causing my 911 to puke fuel on the ground?

[Hi_Fi_Guy]

New to me 1971 911 T. One a road trip and noticed fuel is dripping from the front driver's side fender forward of the wheel. Did it once after a refuel and assumed I overfilled. Parked the car with only 1/4 tank after driving 2-3 hours and it did it again. Any ideas why this is happening? Car has original Zenith carbs but a non original fuel pump. Did not do this before this road trip.

Any ideas or suggestions appreciated.

[Gordo2]

Most likely leaking from the fuel expansion / overflow / vent lines.

Give consideration to checking and replacing the associated fuel lines - like what I ended up doing: Fuel Smell / Odor - Replaced Gas Tank Vent Lines / Hose - 83SC

Good luck,

Gordo

[Hi_Fi_Guy]

Just replaced all the soft fuel lines BUT did not replace anything associated wit the expansion/overflow/vent lines. That has to be it.

Any reason the car would want to vent fuel onto the ground after a long drive?

[Gordo2]

Temperature... If the fuel tank is near full, and temps increase (hot AZ roads) - the fuel and vapors expand which can push the fuel into the overflow / expansion tank.

I used to never fill my tank beyond 1/2 to ensure it didn't overflow (and to avoid the extra weight). No problem ever since I replaced the expansion lines.

Good luck,

Gordo

[HarryD]

Ditto. I had a similar issue three times over a period of about 15 years.

First time it was a failed wheel well expansion tank. Replaced it.

Second time, the vapor lines in the trunk shrunk enough to separate and cause a lot of fuel smell. Replaced all the lines in the trunk.

Third time, was breeding the brakes and noticed the line between the expansion tank and the fender wall was rubbed and failing. Replaced line.