I had a few extruder gears that had locked up bearings from too much CF filament printing.
I drifted out the center pin and disassembled them. There is a tiny roller bearing inside. Soaked the plastic parts in water and the metal parts including bearings in isoprop. After some cleaning and reassembly they are now back to freely spinning. Just wanted to post in case anyone had a similar problem and wants to go on a cleaning adventure instead of spending $25 for a new set.
If you look at the one with the partially removed pin, you will see the direction it has to be drifted out in.
I wish I took a photo before, but basically the yellow wheels were solid black! LOL
