You already have the unit apart aka the rotor pack is out and you just have an oily rotor housing. If not, you need to diassemble it first. I put mine on the driveway, bearing end down on 3 blocks of wood. One centered between the bearings and one on each side of them. I used an old 12" 3/8" drive extension with a socketand carefully pounded them out. I can't remember what size socket, but pick one slightly smaller than the bearing so as to not damage the bore.
Some people drive them through from the back into the case to remove, but I don't think it matters. Do what you feel comfortable with.