Wow, thanks for this thread. I have a 2002 F350 and it's leaking at the fuel drain valve. Replaced the little piece of fuel line hoping that would stop it but no luck. So I did some searching and found this lovely little PDF with instructions to remove and replace the o-rings in the drain valve. Nice clear pics and good instructions. Also, the same company sells o-ring kits. Haven't checked the price yet but here's the PDF link: http://www.dieselorings.com/docs/FuelDrain.pdf