The front bearings on a G11 are actually two individual ball bearings, the factory way of installing these is to first get a set of rubber seal bearings not metal shield (ideally RS type as it has one shield only and is open on the other end, 2RS have two shields and one needs to be knocked out).
Then wash the bearings of any grease found inside them, then pack them with lithium soap high temperature disc brake bearing grease (GC-LB rated) - install one bearing with knocked side inward, pack some more grease in the cavity (dont pack it full) - then install the other bearing with open side facing inward. Then the outer seals.
As the vehicle is run the bearings will always be in a good bath of oil from the grease and provide longest service life. Also make sure the axle nut is torqued correctly, It keeps the bearing preload in check.
what is their failure? water ingress?