Here's a exploded view of what you'll need to disassemble to replace your rotor. They'll probably cost @ $75-$100+ each for new rotors. Put truck on Jack stands, remove wheel, break line assembly, then begin w/ dust cap, replace any worn or striped nuts & repack bearings w/ grease & make sure that what the bearings are encased in isn't cracked or broken. Keep everything in order & reinstall exactly in same order as you took it apart just in reverse.