To replace the spindle you will have to disassemble/seperate it from the front suspension.Here is directions below for the hub and rotor:
Caution : Do not drop spring, ball bearing, bearing race, or retainer.
Note : Remove excessive grease from hub lock and hub splines prior to installation.
CAUTION: After removal, the disc brake caliper must be wired to the frame or otherwise supported to prevent suspending the disc brake caliper by the flexible hose. If securing the disc brake caliper is not practical, disconnect the brake hose from the disc brake caliper. Plug the hose end to prevent fluid loss and entry of air into the system. Upon installation of the disc brake caliper, bleed the brake system.
Remove the integral spacer/seal and needle bearing from the front wheel spindle with an Impact Slide Hammer and Bearing Cup Puller
NOTE: Replacement spindle bearings are shipped with a corrosion-preventive gel. This is not a lubricant. The bearing must be cleaned and replaced with the specified lubricant.
Install the Rolling Diaphragm Seal on the axle shaft. The lip of the seal should face TOWARD the front wheel spindle. Seat the rolling diaphragm seal by lightly tapping on the inner sheet metal lip of the seal with a straight punch to make sure it is sealed squarely.
NOTE: Since the splines on the shaft are phased, there is only ONE WAY to assemble the RIGHT shaft and joint through the knuckle and into the slip-yoke.
NOTE: Make sure the grease seal lip totally encircles the front wheel spindle.