I assume you are referring to the pivot point bearing assembly. On the older bases, the pivot bearing was dropped into a hole in the dog leg platform and then secured in place with an allen head grub screw. To take the older bearing out, simply unscrew the grub screw, and lift the bearing upwards out of the placement hole. If the bearing does not come out, take the vta base off the table and gentle tap the bottom of the bearing until it releases.
The new bearing is a drop in replacement with the exception that it has a threaded bottom which allows the bearing to be tightened to the dog leg support thereby providing better mechanical coupling.
The new bearing is a drop in replacement with the exception that it has a threaded bottom which allows the bearing to be tightened to the dog leg support thereby providing better mechanical coupling.