I would HIGHLY SUGGEST going to Ace Hardware, Menards, HomeDepot, etc.... and buying a torch if you don't already have one. If that "fancy wrench" doesn't get the job done that means you striped the nut... which means you will be dealing with a much more complicated project than you need. You should be able to pick up a decent torch for less than $50 and it will come in handy for multiple projects in the future. I'm a mechanic for Toyota and you learn quickly on in the auto industry that heat is your friend. Heat that fitting up till it almost gets red and I iwll guarantya it will come apart