Abstract
Grease degradation has an important influence concerning vibration level of ball bearings in running time. Resulted sediments after chemical and thermic degradation process alter frequency spectrum, similar with waves on inner and outer races. Unlike with these, the alters bring about sediments that appear and disappear in running time. So, they adhere or detach from race ways. Acquired signals analysis give more details about estimation of ball bearings grease life reserve. Keywords: lubrication, grease, ball bearing, vibration