Replaced rear axle bearings a couple of months ago.

Yesterday I was replacing rear brake pads and noticed that the right axle will slide in an out about 1/8". Since the bearing is tapered, this makes the bearing loose when the axle is at the outer end of its travel.

I pulled the axle and examined the bearing. It looks perfect, tight against its shoulder on the axle.

It seems to me that the method of holding the axle in place is really cheezy and weak. The bolt-down retainer ring under the parking brake barely catches the outside edge (perimeter) of the grease seal, and the inside edge of the grease seal barely catches the inside race of the bearing. The strength of that grease seal is all that holds the axle in place. If the grease seal bent under the force, the rotor would hit the caliper.

What am I missing here? Or, what did I do wrong when I assembled it?