KJ, it should all fall apart at that stage. Did you try heating it up? Mine had loctite holding the allen screw in place, it would not unscrew at all until i put it in a bag and boiled it for 5 minutes.
**Edit** Just looked at my Z52 again, removing the allen screw should let that metal piece in the middle fall out. The plastic retaining ring is behind this, and is easily unscrewed with some needlenose pliers.