I need help in the function of the fuel shut off or (bleeding valve?) on top of my fuel filter. It's leaking from the stem.(Plasic cap was broken off when I got the car)
What position is the valve need to be under normal operating contiditions? When I crank it all the way down, the engine shuts down, and any other position it leaks. I've ordered a new valve and washers for the system, but is there any trick to putting it in? Please help?

Tom Little
95 E class D
145,000 miles
Spring Lake, MI