Fuel supply and return which is which?

[Homeoboxter]

Originally Posted by gdotcvg

My fitting at the blue arrow is slightly wet/weeping. Does anyone know whether there is an o-ring in the disconnect fitting that can be replaced? Other options of repair? And my vote is that it (blue arrow) is the return line (98 base)

Mine was leaking too, but not at the connector, but at the fuel rail, and it was leaking down on the back side of the line. If it leaks at the connector, it`s also possible that the line itself is scratched where the fitting slides onto.