[MikeB]

Got the info below off the Interweb. And you might want to start by over-tightening while spinning the wheel to make sure everything is seated.

The following procedure is one method for adjusting the end play in a wheel bearing set.

Tighten the adjusting nut while turning the rotor. When the effort to turn the rotor increases, a preload is placed on bearing assembly and all raceway surfaces are in contact, providing no end play. Back off the nut one flat to allow insertion of the cotter key. The end play can be checked with a dial indicator. Mount the indicator with a magnetic or mechanical base as close to the center of the hub as possible. The indicator tip is set on a smooth surface at the end of the spindle. Push the rotor back and set the indicator to zero. Then pull the rotor or drum out and read the dial indicator.

Allow 0.004-inch (0.100 mm) ± 0.003-inch (0.076 mm) of end play, then lock the nut with a new cotter pin. Whether you are checking a conventional wheel bearing or hub bearing, the best tool for checking adjustment is a dial indicator. Many four-wheel-drive vehicles and most trucks with a load rating of one ton and higher use a full floating axle. The axle has a bearing set, spindle and hub. The same adjustment procedure can be used for these applications.