Tank Assembly problems of the 2010 Mercedes Benz GLK350

Fuel leaking near the rear passenger side coming from top of gas tank near fuel sender. Smell of fuel in vehicle cabin when filling the gas tank to full. Noticed a steady leak of gasoline with 30 drops a minute (when full) and puddle of gasoline on garage floor. The smell of gasoline subsides once the tank is below half full. Fuel leak only when gas tank is full.

Fuel/gas tank leaking after filling up the tank. Car smell of gas and pool of gas observed on the floor of the garage. I have to backed up the car on the street to avoid possible fire on my property. This is the second incidence. . . The first incident was a week ago, the car smells of gas and I brought the car to my mechanic and he can't find any leak in the fuel system nor on the fuel tank, the gas tank was half empty at that time. After filling up the tank on 4/10/13, that is when I've noticed that the gas is leaking (pool of gas on the floor) from the fuel tank after parking in car at home.