1. INDENTATIONS OR BREAKAGE OF THE SHOULDER DUE TO INCORRECT FITTING
EVIDENCE
■ Presence of indentations located on the edge of the track and often seen over the complete circumference of the ring.
■ The indentations are in line with the position of the rolling elements.
■ Damaged or broken shoulder.
■ A slapping noise to the assembly.
CAUSES
■ The bearing was off-centre when fitted.
■ The bearing fitting was incorrect.
■ The bearing was dropped onto a hard surface.
■ The bearing tightening load was transferred through the rolling elements.
EXPERT ADVICE
■ To avoid damaging the bearing, do not apply load on the inner ring.
■ Follow the general fitting recommendations.
2. SCRATCHES ON SUCCESSIVE BALLS FROM AN UNTIGHTENED DRIVESHAFT
EVIDENCE
■ Damage with circular grooves deforming the surface of the balls.
■ Grooved scratches, similar to ‘petanque’ balls.
■ Matching damage on the bearing tracks.
CAUSES
■ The vehicle was moved without the driveshaft or hub nut in place (such as when being serviced).
■ Damage on the balls from contact and rolling on the inner edge of the track, due to a gap between the inner races.
EXPERT ADVICE
■ Avoid moving any vehicle when the driveshaft nut isn’t tight.
