Cal - I would concentrate on the bad screw and try to get it uniformly tightened down. In my mind, the unequal pressure would likely cause the oring to deform resulting in a leak no different than a deterioated oring does. All the fuel line seals are touchy.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)