Any ideas how the a/c clutch barring comes out ???

I am trying to remove the barrings on a 93 astro. When the car is running, it makes noise, and I saw it is comming from the front of the ac compressor, which is the pully with some barring inside, and it is grinding/metal shavings all over. I know it must be a barring, but I already removed the front center nut, but for some reason it is not comming out. I tryed pulling it and wedging it with a screwdriver, but nothing works. I can move the pulley behind it, and it wigles like crazy, but I cannot get to it because of this front cover, any ideas how this is supposed to come out????? I would appreciate any help. Thanks.