AC leak - I think I know why

[Dixie]

Someone confirm my suspicion about why my rebuilt compressor leaks. (You may recall, I refreshed my A/C system about a month ago. One thing I did was rebuild the compressor.)

You see, the brand new shaft seal is leaking, and I think I know why. It's because I couldn't figure out what the heck the o-ring was for, so I left it out! Upon studying the picture below, I now believe the o-ring is supposed to go around the metal retaining ring.

Is this correct? If so, I'm either running the original 1988 o-ring, which would explain the leak, or I have *no* o-ring, which would also explain the leak.

The good news is I undertook this project as a learning experience, so I'm not bummed.