I have a different yet SIMILAR variable pulley on my Murray 46" mower, the center pulley is made to be loose so it
can move up & down changing the driven belts ratio, I am not aware of these types of pulleys having any bearings
on the center pulley assy. it appears yours just has bushings or sleeves, I'll have to do some research ... in the meantime another member might offer advice, hang tight, ... Boobala