gas tank hose stuck

Hi there,

My gas tank is almost off. 2001 Dodge Caravan that is, and the breather hose I guess it's called runs from rear top of tank to a little metal cylinder bottle under the filler cap.

the hose runs through the frame by the left rear shock and there's a connector there that I can't undo. I fiddled with it for over an hour and almost busted up now...

My gas tank is hanging by this hose and slightly supported by a floorjack!

How do I disconnect this hose?

Thanks,

Gordon