You just have to remove the nut on the tapered spindle on the motor and lift the linkage bar off the taper. Sometimes you have to pry the link off the taper a little, then simply reindex the wiper. BE SURE THE IGNITION IS OFF WHEN YOU DO THIS because if it is on and you move the motor off its park position, the wipers will suddenly start and hurt you.

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1987 W201 190D