It looks like my second unit isn't the same as the one you have either. It's made by Repa, Mercedes part number 114 860 1485. I tried clamping the belt to the frame to secure the wind-up spring, so the plastic sleeve is not clamped. On mine, the sleeve can be moved a very little bit.

The infamous slot with the loop and rod in it are covered by part of this plastic, and the plastic will get broken to remove the loop/rod with the screwdriver, unless you take care to slide the plastic sleeve around a bit to expose the slot.

I'm not sure if the pictures in your original post show the same slot where the belt goes into the center cylinder. I thought they did, and assumed that there was another slot directly opposite. Maybe yours is different... but how is the belt on yours held in the cylinder? On both of mine, the loop and rod is the same, there are 2 slots, and only the ratchet/cylinder design are different.

If I were you, at this point I'd take the worst one of the retractors, one with a good belt, and drill/grind out the rivets holding the side covers on, and completely disassemble it to figure out how it works....and post back please so I can get some sleep LOL

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1986 560SL
2002 Toyota Camry
1993 Lexus