Re: Oil filled hubs /bearings ?
The idea behind packing bearings is really two-fold. First is obviously to ensure the bearings have a clean supply of grease. The other is to visually inspect the bearings for pitting, overheating (blueish tint), cracks or other damage from water that can get into the hub. Just keeping it greased is not a guarantee that bearing failure will not occur. As a minimum, each wheel should be periodically jacked up and spun by hand while listening carefully for the ever so slight rumble of a rough bearing. If its loud enough to hear, its bad enough to require immediate replacement. If the trailer is in storage for long periods, put it on jack stands and spin the wheels periodically to keep the bearings from marking the races which can evenutally lead to failure.