Remove the tire. Unbolt brake caliper but don't let it hang from brake line. Slide the caliper off. If rear wheel put car in neutral before pulling off rotor.
Support the front of the truck on jack stands and remove the wheel. Unbolt the caliper and hang it by a string, not by the brake line. The rotor should then just pull straight off the hub like the unbolted wheel did. Replace the pads at the same time.
Jack the front in up so that the wheel spins freely, remove the wheel, remove the calibers, and pull off the old rotors. After that, reverse what you just did.
