Your question isn't clear. The seals usually last the life of rotor or bearings inside and are not a maintenance item for replacement. generally they are only removed when replacing bearings or installing a new rotor and even then, if careful often can be reused.
leaking grease or cracks Looseness
There is no oil. Wheel bearings contain grease.
Check
Bearing & seals will run you about $150-$200 for parts and about 2 hours labour
sounds kind of early so better get new seals too
check your wheel bearing
check your wheel bearing
Loose wheel, bent wheel, Belt broke in tire,BAD wheel bearing. Check and repair as needed.
check the wheel bearing
This sounds like a wheel bearing issue. Raise the front wheels and turn them by hand. They should turn smoothly with no hint of a vibration unless the bearing is bad. Also check for play in the bearing by rocking the wheel in/out at the top/bottom.
Begin by removing the tire and wheel. Remove the and of the axle. Remove the wheel bearing nut. Remove the wheel bearing seal and the wheel bearing. Reverse the process to install your new wheel bearing.
Remove the tire and wheel from your Mercedes-Benz. Remove the axle end. Remove the wheel bearing nuts. Remove the wheel bearing seal and the wheel bearing. Reverse the process to install the new wheel bearing.