Hey mearsman I looked at a diagram of the crankcase and I'm pretty sure the hole you are referring to is the oil return. Oil is pushed to the crank bearing and out the side to lube the seal. Then the oil returns to the case through the small hole. Make sure there is no debris in the hole to plug up or oil will forced out through the seal continually. You said the bearing is within tolerances so that shouldn't be the reason for seal failure. Is the seal leaking on the crankcase side(outside) or the crank side(inside)? Is the crankcase breather plugged or restricted?