Remove pinion nut. Tap off yoke with hammer. Remove old seal. Install new seal . Reinstall yoke and nut. If reusing bearings tighten pinion nut until you have 6-8 in lbs of rotational force. You will need a dial in lbs torque wrench. Some people have also had luck taking a punch and making a line on pinion and nut and tightening until they line back up at the end.