The components of the fan hub bearing.
From top left, clockwise...
The fan hub, the dual row 17 x 32 x 14 ball bearing, one of the two bearing cages used to separate the ball bearings (one inserted into each side), one of the two bearing seals (one inserted into each side) and the snap-ring that retains the bearing in place.
The snap-ring is next to impossible to remove due to the design. One end is angled such that it cannot be used to extract the snap-ring, and the other end, although angled correctly, is no better.
A small grinding stone on a Dremel was used to weaken the end opposite the open end of the snap-ring in order to weaken it so that it could be collapsed enough to extract it.