Step three: Clean the cup
Wipe the bearing surface with a rag and inspect for wear or damage (see introduction for common causes). Bearing surfaces are unlikely to be replaceable. “It’s an integral part of the hub,” says Jon.
“If it’s pitted, you need to make a call on whether you’re prepared to run the hub rebuilt with new grease and new bearings, but with a slightly pitted cup, or consider having the wheel rebuilt.”