I'm not really sure about the correct thread size. I would go to Napa, (or what ever parts house you go to), and buy a couple short sticks of metric fine thread brake hose, Different sizes tho. There are only a few different options to choose from. Ge the size you need and take the ones back you did'nt use.
I wish I could be more help, but I can't find my manual to tell you for sure. It's prolly something along the lines of M10x1.0 Thats my guess.
Mike