Dirtyd0g said:you can grind a cheap 5/8 wrench(I believe it is 5/8) into a point at the end and pop it in there. I have had several different tools I used. The best was a tightening wrench from a die grinder. I do have one of the "special" tools however it bends way to easy. Definately spray some wd-40 on the fitting first.
Alan