On a RWD there are 2 tapered roller bearings used on the front wheel hub of the rotor. The outer, which is located under the spindle nut & washer, and the inner which is the larger of the two and is located on the back of the hub/rotor under a grease seal. To remove the rotor to get at the rear bearing you must remove the front brake caliper and its bracket.
Both bearings ride in races, which are pressed into the hub. When replacing wheel bearings it is advised to do both the inners & outers and the driver and passenger sides at the same time. Never install a new bearing w/out replacing the race. You'll also need new seals for the rear bearings. To grease the new bearings, put a glob of grease in the palm of your hand and drag the bearing through it until it comes out the back side. Also put some grease inside the hub. Use a quality wheel bearing grease specified for disc brakes and recommended for Ford. It is critical that the spindle nut be torqued properly during reinstallation of the hub/rotor. There is a torque spec, but I tighten the nut, spin the rotor a few times then loosen the nut and tighten it to zero-lash (by basically just using the weight of the large wrench) and then reinstall the cotter lock and cotter pin. If you have to move the nut to get the cotton pin to go through the hole, loosen it rather than tightening it and always use a new cotter pin.
Note: If the rotor is a tiny bit loose (wiggling the tire side to side) when cold, that's a sign you didn't over tighten the nut, as it will tighten once the rotor warms up and expands.
Tip: If your rotors need replacing, new ones come with new races already installed in them and will save you some time and effort.
