Step 1 for servicing the clutch on a Windstar is to "remove the compressor." Since I'm not overtly familiar with your van I'd wager it's simply inaccessible while mounted on the engine.
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You should have a Nippondenso FS10 compressor, which has a fully replaceable clutch and coil assembly. It's advisable to replace all of it instead of the bearing only.
In addition, the clutch and coil are press-fit units which show a few special tools for removal (although these could probably be fabricated).
Bottom line is Chris142 is probably right. It's not worth screwing around with all of it when you can buy an entire compressor kit (with clutch & coil, accumulator, orifice tube, expansion valve) for under $200.00.