I decided to change the fuel filter on my 4630 and 6600 both have the 404 engines. Problem is now I cant get the air bled back out of them. Put a new primer pump on the 4630. I can get almost all the air out but not 100%. The 6600 is the real PITA since the filter is on a slant and the air is not near the bleed bolt. Any tips would be appreciated.