Tools: High-temp axle grease; Pliers; Hammer; Punch; Wrenches and sockets; Grease gun (not mandatory); Bearing packer(not mandatory).
Basic sport truck maintenance isn't as much fun as bolting on a supercharger or a trick set of wheels, but proper care of the less glamorous parts of a truck--the stuff that doesn't contribute to performance--is mandatory. A worn-out suspension, bad brakes, sloppy steering, and the like aren't visible to the cruising crowd, but they must be in optimum condition to make the truck safe and fun to drive.
Those lowly wheel bearings require periodic attention too. Hidden behind the wheel under a little tin cover, wheel bearings are virtually invisible, and even if you install the world's trickest ones, you'll gain not one iota of performance. But even if it's just repacking them with new grease every two years, your wheel bearings need attention. They're lonely.
The following shows how to repack wheel bearings with a disc brake car (this one is a Mustang). Drum brake setups are similar, except that the drum must be removed first. This is a gooey, messy affair, so be prepared with plenty of disposable rags.
With the wheel and tire removed (as well as the brake drum, if so equipped), note the tin cup dust shield smack in the middle of the rotor or wheel hub. Remove it with channel locks or pliers or by prying with a screwdriver. Remove the cotter pin, as shown, and the brake caliper too. | 
Remove the spindle nut (it should be fairly loose), then the rotor or hub. Be careful when removing the rotor, since the outside bearing and washer (arrow) can come off with it. |
The outer bearing shown in the previous photo will fall right out. The larger inner bearing mounts on the backside of the rotor and is contained by a seal that must be pried out with a small screwdriver. Inspect the bearings for wear, paying particular attention to the bearing races, which are the bearing contact surfaces pressed into the rotor. If there doesn't appear to be any appreciable wear, chances are you can reuse the bearings. If you see loose metal, pits, or roller bearing wear on the races, install new bearings. Use a hammer and a punch to drive out the races. This step requires the most patience. | 
Install the new races by lightly tapping them into place with a hammer, then drive them home with a hammer and a piece of pipe or a socket that's just a hair smaller than the outside diameter of the race. You can also use a punch. If the rotors need turning, as ours did, the races must be installed. |
If reusing the old bearings, thoroughly clean them in solvent and then blow dry with compressed air. Never spin the bearings with compressed air, doing so runs the risk of knicking the rollers. To pack them, put a wad of the appropriate high-temp axle grease in the palm of your hand and push the bearing through it several times, as shown. Work the grease through the bearing rollers, and continue until it oozes out the other side. You can also buy an inexpensive bearing packer that works with a grease gun. It lessens the mess a bit, but isn't necessary. | 
With the bearing packed, you can now reassemble the brake assembly. First, install the inner bearing, then the inner seal; install the rotor on the spindle, then slip the outer bearing into the rotor, then the washer, then the nut. Second, tighten the nut all the way down with medium force to seat the bearings, then back it off a half-turn. Finally, tighten it back against the washer with light force, and back it off just a bit. You want to keep slop out of the bearings, but not apply force to them. Install a new cotter pin with the ends bent over the nut to keep it from backing off, then reinstall the cover, and you're done. |