A bearing packer is a tool used to simplify the packing of grease into wheel bearings. Wheel packer kits often enable old grease to be flushed out and bearings repacked efficiently and with less mess. In the case of tapered roller bearings, the bearing is placed in the packer with the taper pointing down. The cone of the packer is then screwed down on the bearing. A hand-operated grease gun is applied to the fitting on the center shaft of the packer and grease forced into the bearing and our around the rollers in the cage. (Some bearing packers come with a supply of grease.) Pushing on the cone handle forces the bearing down onto the packer, squeezing lubricant into the bearing.