Saginaw power steering pump rebuild....shaft retaining ring?
 

Just resealed and installed a pressure reduction kit in the p.s. pump. Haven't reinstalled it yet, but it occurred to me that the little ring retaining the pump shaft from inside the pump doesn't seem like it would prevent the shaft from pulling out of the pump. It doesn't look like the typical steel snap ring that I've seen by googling pictures of disassembled pumps, but it looks almost like it's made out of aluminum or some other soft metal and allows the shaft to be tapped through the front of the pump. I haven't seen any examples of this type of retainer online. I also haven't found any rebuild kits that contain a snap ring.

What am I missing here?