A fluid filter assembly includes a housing, a service cover, a center tube removably secured to the service cover, a filter cartridge removably sealed and circumscribing the center tube, and a seal arrangement. The seal arrangement is between the center tube and portions of the housing to close a drainage channel to the flow of clean fluid flow therethrough, when the fluid filter assembly is operating to filter. During normal operation, the fluid filter assembly operates to allow fluid to flow into the housing through an inlet channel, through the filter cartridge, through openings in the center tube, and out of the housing through the outlet channel. Methods for servicing include removing a service cover from a housing to remove, together with the service cover, a center tube, and open a drainage flow passageway from the housing. Next a filter cartridge is removed from the center tube, and a new filter cartridge is operably mounted on the center tube. Next, the service cover with the center tube having the new filter cartridge is operably mounted in the housing to close the drainage flow passageway. Methods of filtering will direct fluid to be filtered into a housing having a removable and replaceable filter cartridge; then direct the fluid through a tubular region of filter media in the cartridge; then through fluid openings in a center tube; and into a clean fluid flow passageway. Example methods include preventing fluid to bypass the filter media by removably sealing the filter cartridge to the center tube. Example methods will also include preventing fluid from flowing into a drainage passageway by removably sealing the center tube to other portions of the filter housing. Systems utilize filter assemblies as characterized herein include fuel systems, lube systems, and hydraulic systems.