The side of the the fan hub adjacent to the cooling fan.
The three threaded holes are M6 x 1.00.
The fan hub bearing has been removed. Part way down the bore is the groove for the snap-ring that holds the bearing in place. The bore above the snap-ring groove is where the bearing is mounted. The bore below the snap-ring groove is slightly larger in diameter so that the bearing drops out when it is pressed out beyond that point.