I bought a Mutoh XPJ printer about 8 months ago. Mutoh's instructions say to clean and re-lubricate the bearing raceways once a month. My first question is why? These bearings are totally enclosed and permanently lubricated. Do they slide along the raceways or roll along the raceways or both? None of the lubricant on the raceways can get inside the bearings. So why put lubricant there? My second question is what is the best way to apply lubricant to the top and bottom, inside raceways where you can't see what you are doing?