Hyundai Repair: Fuel Filter not sealing in excel, hyundai excel sprint, hyundai excel

Question
My partner is servicing my Hyundai Excel Sprint 1995 at 145,000 km.  Everything was going ok until he replaced the fuel filter.  The old one was full of black stuff inside.  The car starts fine but the new fuel filter doesn't seem to be sealing properly and there is petrol leaking when the car is started.  It looks like it is coming from the top and dripping down.  What could the problem be?  He has tightened everything as much as possible, many times over.  And as a side point, this excel has been garaged for a few years and not used much.  Then last service done was in 1998.  I have been driving it for the last 3 months and everything has been fine in it.  Thanks for your help.

Answer
Depending on which style fuel filter you have, presuming it's similar to those used in the U.S., the fuel lines seal at the fuel filter via a rubber o-ring in the fitting or by copper washers.  

The type that has a bolt going through the center of a fitting on the end of the fuel line has copper washers.  If further tightening won't stop the leak, you probably need new sealing washers.

The type that has a pipe with a flange on it that bolts onto the fuel filter has an o-ring on the end of the pipe that seals against the fuel filter.  Check the o-ring to be sure it's not damaged.