saph cos rob

iTrader: (11)

hi guys, since owning my 3dr ive noticed a bit of a whiff of fuel in my garage (never had this with my old sapph) ive traced it coming from the vent pipe under the car, the tank has a pipe coming out of the top, runs through a valve type looking cylinder up by the filler neck (see pic below) then vents off underneath - after taking this valve (?) off ive found it to be completly hollow? im sure my old one on my sapph had some sort of ball in it, if i look though the inlet pipe i can see daylight out of the other end? how are these things ment to work, as you can see from the pics its sealed and looks like its never been tampered with