Jimmi what those instructions are talking about is the large area inside the hub between where the inner and outer bearings are located. There is no reason to fill or even part fill that area with wheel bearing grease. If the bearing is fully packed and you slather a generous amount of grease around and slightly over the bearing races you are good. I worked in a gas station (they were actually called service stations back then) as a kid and wheel bearing packs and brake adjustments were as common as oil changes. For some reason many people filled that entire cavity and sometimes even the dust cap full of grease. Made for a fun job cleaning it all out. That's probably why they have the instruction not to do that. That is basically what "bearing buddies" do on boats. They use a grease fitting to completely fill the hub with grease keeping out the water. Fine for hubs going underwater but not necessary on our old trucks.
Chuck
