I have an 82 300SD. The last two days, I have had a puddle of fuel on the ground near the passenger rear tire. Today there isn't one but my I'm now on 1/2 full. I suspect that the leak may be on a fixture that is on the upper half of the tank. I was wondering what the most likely spot was or if there was a "typical place" where you would get a leak.

Secondly, if I'm going to get into this I thought I might start replacing my fuel lines with Vitol fuel lines in prep for running biodiesel. Does anyone know what diameter lines I would need? Are there any pitfalls I should watch out for?