Hub cap for a wheel end assembly, wheel end assembly, and axle assembly

A vehicle tire inflation system (14) includes an axle assembly (12) with an axle housing (20) having an air supply conduit (22). Air is provided to the air supply conduit from an air tank mounted on the vehicle. The axle includes least one wheel hub (24) rotatably supported on the axle housing by bearings (26). A hub cap (34) is mounted at one end of the wheel hub and has an air passageway (36) for conducting an air supply through the hub cap to a tire (16). A filter (50) is installed within the passageway to remove any debris from the air supply.