Here is the final fuel-line connection at the fuel-sending unit. When installing the fuel-sending unit, it's a good idea to coat both sides of the cork gasket with Permatex aviation gasket sealer. The original fuel-sending-unit retaining screws had a groove machined in them to capture the O-ring, which completely seals the screws and sending unit. Replacement screws may look correct, but this important groove is missing. Coating the screws with Permatex ensures proper sealing.