The seal lip contact area is cracked, scratched, or cut
Possible root cause
Mounting tools or cones with sharp edges during installation, seals slip through shaft defects during installation, seals slide through shaft holes, keyways, or splines
The edging method is not consistent during the manufacture
Damage caused by packing or handling
Possible solutions
Protect the seal lip by covering splines, keyways, and holes with chamfered bushings or wrapping to keep screwdrivers and other sharp tools away from the seal lip
Check the seal lip before installation
The seal lip contact area is cracked, scratched, or cut