Paccar fuel filter doesn't stay full

[aaronb]

This is what it looks like in the housing. No way for a draw tube I can see. There's a pin on top of the filter cartridge that pushes that ball in to let the fuel flow through. There's not a big hole in the center of the cartridge to slide around that tube because of the pin and that ball in the housing.

I had a 30 micron filter instead of the 10 micron filter I have been running. It seems to be doing better with the 30 micron cartridge. The filter is staying almost full. There's a compucheck fitting on top of the housing and one by the secondary filter for helping remove air. I'm going to get the hose to connect to them and try removing any air. I wonder if at some point when the filters were changed if it has gotten air in the fuel system.