Originally Posted by Towboy
I don't believe a ball valve will make a difference as after the filter was removed no diesel leaked out I had filter off for an hour not a drop I guess cause I had the rear of coach higher than the tank and gravity didn't effect it. Seems there was fuel trapped above the filter in the header.
OK, with no shut-off valve, you have a choice:
If the tank is higher than the filter, fuel will run out-- a lot of fuel.
If lower, fuel will flow/siphon back to the tank making priming a REAL JOB.