Was helping a friend out today doing the brakes on the front of his "96 F150. The rotors/hubs were shot so he had gotten me a new set to put on. Before I put the new bearing and seal in I happened to look inn the middle of the hub, between the races, where it"s still an unfinished casting. It looked odd so I rubbed my finger around inside of it and sure enough it still had a layer of casting sand stuck to it. I gave it a good wire brushing and the blew and washed it out in the parts washer before putting it on. Just got me thinking, man wouldn"t that have been a nice thing to have get into the bearings. Sure would make a mess of them in a real short time. So, just a word of warning, if you have to get a new set of hubs/rotors make sure to check them good before putting them on.