I wouldn't say no one can replace the rotor cartridge bearings because it's been done up here by one of the fellows in the SCCOO in Ontario. Now mind you it is not easy but can done , it uses the same bearing as the smallest one in the snout. The biggest issues is no one can source the small red and green seals that sit on the inside of the rotor cartridge on the inboard side of the shafts. One can only hope theirs are ok and can be re-used.