Good evening. This is my first post in this forum. So go easy. Right now I have my radiator out of the truck for a repair on the bottom seam. Anyway, since it was out I decided to fix the fuel leak that was coming out of the filter on the passenger side of the truck. Since I'm running a blend of fuels the fuel is somewhat dark, and with the radiator out, it made seeing what I needed to do more visible. Judging by the leak it appeared that it was leaking out of the threads and running down the copper line that runs under the front rail. So I unscrewed the nut and seen that it had an internal flare fitting. Cleaned the threads up, both on the nut and inside the elbow coming out of the filter. When I put it back together and tested for leaks, the old leak was fixed but now I'm getting a new leak that comes down the middle of the nut. Everything looked good before putting it back together, felt like a nice fit. Tightened the fitting up till wrench snug plus a good cinch. My questions are, did I miss a step, is there supposed to be an o-ring in that connection, and what ideas do you have to stop the leak?