Park the trailer on a level surface and chock the wheels
Raise the trailer and support it securely with jack stands
Remove the wheel and hub assembly
Take off the dust cap, cotter pin, spindle nut, and washer
Slide the hub off the spindle carefully
Remove the outer bearing and inner bearing
Clean all old grease from the bearings, hub, spindle, and races
Inspect bearings, races, seals, and spindle for wear or damage
Replace any damaged parts before reassembly
Pack the bearings with high-temperature wheel bearing grease
Apply grease evenly through the bearing until it comes out between the rollers
Fill the hub cavity with a moderate amount of grease
Install the inner bearing and a new grease seal
Reinstall the hub onto the spindle
Install the outer bearing, washer, and spindle nut
Tighten the spindle nut while rotating the hub
Back off the nut slightly and set the bearing preload to proper specification
Install a new cotter pin or retainer
Reinstall the dust cap
Reinstall the wheel and tighten the lug nuts
Lower the trailer and torque the lug nuts to specification
Check for smooth wheel rotation and proper bearing play
Recheck grease and bearing condition regularly
Use a grease gun only if the hub has a grease fitting and compatible bearing system