1995 gas tank pressure

[mini winnie]

There is a mild gas smell and when the gas cap is removed there is a large amount of built up air pressure in the tank. We have had it in for repair twice with broken seals. The gas tank is never below half a tank. Does anyone else have this problem and what is the fix? Our volkswagon mechanic is not able to provide any solutions. Thanks Brian

[newuserguy]

I have a similar problem on my 1997 Rialta. Fuel gauge was showing full when it should have been 3/4 to half full. Smelled gas. Pulled over and heard gurgling from the fuel tank. Releaved pressure from tank by slowly opening gas cap. A lot of pressure vented. Allowed vehicle to cool down for about 20 minutes. I was driving in direct sun at about 85°F. Problem went away at night when it cooled off. Fuel tank is about 6″ off the ground and can get hot if it's hot out. I got a code P0440 – Fuel Ventilation System. Not sure what's wrong with it. Will post if I find the problem. Also, gas gauge was reading accurately and there wasn't so much pressure once the temperature went down.