580k fuel drip

i notice a drip from the bottom of the smaller fuel filter on the 4-390 engine . i pulled the filters and had a spare filter so i put it on and still a tiny trickle coming down the backside of the back filter not the seperator what the hell i cant see where it comi ng from , try another brand filter ? while i had them off i don,t seee anywhere else it possibly coming from .. crap i had about a ounce overnight in bucket , totally perplexed

580k fuel drip