121.1. The wheel bearings shall be inspected so that the play measured at the outer circumference of the tire does not exceed the manufacturer’s standard or, in the absence of such standard, no discernible play may be detected.
The bearing shall be properly lubricated and its lubricant may not be under the minimum level when visible through a sight glass. Bearings shall show no damage or leakage, other than oozing, and shall not cause abnormal noise.
The filler cap, drain plug or hub cap may not be so damaged that the inside of the hub is exposed, insecurely mounted or missing.