Can you just replace a bearing on an AC compressor?

No, you cannot simply replace a bearing on a standard residential air conditioning compressor because hermetic and semi-hermetic compressors are permanently sealed units. The internal motor and mechanical components, including the bearings, are enclosed inside a welded steel shell that is designed to be airtight to prevent refrigerant leaks. Because the manufacturer welds this casing shut at the factory, there is no physical way to access, service, or replace individual internal components like bearings without cutting open the shell, which requires specialized industrial equipment and is not economically or practically feasible for field repairs. When an internal bearing fails within a sealed compressor, it creates catastrophic mechanical damage and metallic debris that contaminates the entire refrigerant and oil system. Therefore, the standard and only viable industry repair procedure when a compressor bearing goes bad is to replace the entire compressor unit or, more commonly, the entire outdoor condensing unit if the system is older.