Hello friends, you've helped me before with a lot of things in my all life dream car, my Rabbit GTI. Now he started a new battle with me, everytime I put over 3/4 of the gas tank capacity he starts pouring it from the gas cap, it's really dangerous and irritant, I've checked the conections below the car an I've eliminated the hose that goes to the carbon receiver on the front right side under the fender. Now the hose that I assume that let the gas fumes go out of the tank is unblocked, so there should be no reason why pressure is created inside of the tank. I removed earlier some piece that let the gas come in but don't let it out throug the filler neck because the spring that suppose to hols it was missing.
I reallyhope that you can help me. Thanks and greetings from Cuba, Juan.

See attached image... I hope I attached the correct one.

- remove the breather hose #7 from the side of the filler neck
(this is also a good time to clean all the dirt from around
the filler neck in the wheel well).
- remove the small vent hose #26 from the gravity valve #24

• blow through either hose and see if you feel air coming out

of the other

*** gas vapors will also come out, be careful what you inhale ***

If no flow is felt... something is plugged, find the plug
and un-plug.

- check the gravity valve (should rattle when shaking)

• 1A is the flap in the gas tank, remove the filler neck

#3 and rubber hose #11 to see if the flap is stuck

I too am a little rusty when it comes to these older cars.

Maybe tcovenant2000 (aka Thomas) can confirm these suggestions.

My car always had problems with the fuel system, maybe because he was stopped for almost 8 years. When I got him the gas tank was broken so I took it out and fix the opening. I've told you before at the forum that the previous owner took off the FI and installed a carb, to do that he disabled the electric fuel pump, I think that he did a new hole in the tank for the new fuel line, it is at the right side, looking from the back of the car, very low in the tank, producing sometimes very ugly dirt deposits the stuck the fuel flow, I don't think that the original fuel hose were attached to that place. Anyway, the only work done in the tank is the fixing of the hole, I checked all the conections, and I even disconected the gravity valve and the carbon deposit in the front of the car, so the vent hose is free over the rear wheel (just to verify if the fuel issue continues, I don't drive him that way). I also took away the piece that let the fuel just go in the tank but don't let it out. I believe that the problem is at the gas cap. It does not seal the fuel filler, but it doesn't have any logic, I don't know how the fuel can travel all the way up to the filler and the vapors inside don't go out through the vent hose. It's driving me crazy, I can't use the car, and when I do, I'm always worried about it. Thanks for all the replies, the diagram of the tanks is very useful, thanks again.