Is this something I can do easily? I have some flare wrenches, but looking up under the car it looks like there will be some things in the way trying to get to the bottom end.

 Any advice or suggestions? If I cant see it well or get to it easily I tend to give up.

 Also if it leaves a good sized puddle under the car where its parked,is it less likely to be the hose and more likely the rack leaking?

 The pressure hose was leaking at the top about 6 months ago and had someone look at it he just replaced the o ring at the top of the pressure hose. It stopped leaking for a while, so Im assuming its likely the lower o ring gone bad since they probably would go about the  same time. But Im assuming, and afraid it might wind up being more major.

 I tried to get the top part loose with a 5/8 line wrench but I think I needed a metric one it didnt fit real tight. I found someone to do it for $30 so it wasnt too bad. I think I could have done it if I had the right tools. Its supposed to be 5/8 I thought. I started rounding the nut on top so I quit right away.