The clutch pilot bearing is a ball bearing pressed into the flywheel but that is greased in the factory and does not require additional lubrication. It is intended mainly to serve as a support to the front of the transaxle input shaft, but it should be examined when the clutch components from the engine are removed. Because of its inaccessible, this component should be replaced if there are doubts about its condition. Some procedures won't apply to a car if the engine has come out. First you take out the transaxle and the clutch components. Take a flashlight and look inside the bearing for any sign of wear, scoring, being dry or being rough; if anything looks off replace the bearing. Using a hammer and drift you will need to drive the bearing out of the front to the rear to remove the flywheel. To install a new bearing, grease lightly onto the outside of the bearing and drive it into the recess using a bearing driver or socket. Finally, reinstall the flywheel, clutch components, transaxle, as well as any other part which you've removed previously, and secure all fasteners to the same torque values as before.