Securely jack the truck up and remove the wheels. Then unbolt the caliper from the rotor and secure it off to the side with wire or rope so there is no weight on the brake lines. Then remove any axle nuts or pins if it is a 4wd. Then remove the rotor and install the new one.
Remove the dust cap from the spindle assembly. You will see a lock nut and bearings beyond the dust cap.Pull the cotter pin from the lock nut with a pair of pliers.back the lock nut out with a wrench or a pair of pliers.Pull the rotor off the spindle.
First jack it up and remove the wheel. Remove the retaining clips, compress the piston, and remove the old pads. Remove the caliper, then the rotor. If it hasn't been changed in a while, you may need to pry it off.