I think sometimes too that if you have a really good seal at the bridge hole, the residual heat may be pressurizing the cart and pushing fluid out the vent. Thats why I started backing my cart off the bridge a bit when I am done...PITA...but seems to prevent that.
Nicotime thats some nice art work there! I did a vent threw the back of the resivor with pin hole but thats as far as I got, soon as I started to drip juice in it actually leaked right out the back of the cart like a beer .... so I stoped there... but using a tube to go out the resivor into the chamber where there is only air is pretty good idea... nice