FYI: 1987 W201.126 190D 2.5
* The woodruff key is deleted.
* The large washer is superseded, and the new one does not have a woodruff key slot.
* The pulley is superseded, and the new one does not have a woodruff key slot.
You must use the correct "recessed shoulder" factory nut to get enough tension on the pulley so it does not slip.
The only way I was able to torque the (new) nut tight enough (to not slip the pulley) was off the car with an impact gun.
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