On some alternators, once the nut is off the pulley will just fall off. You can use an impact wrench or if you don't have one hold the shaft with an Allen wrench and loosen the nut. Did you get the old alt tested? A slightly loose belt would cause the volt readings you posted. When the new alt is put n the belt gets tightened and majicly the problem is fixed. The test we used is with the engine off try and turn the alt over with the alternator fan, hope this helps. jay 6155
