I aquired an old Atlas horizontal milling machine model MFC. The arbor support appears to be mounted backwards on the support arm, the busshing that would hold the arbor is facing away from the spindle. I removed the mounting bolt and tried to remove the support from the arm but it is holding fast. Looking at the parts breakdown there appears to be lock that are held in place by the mount bolt. How do I remove these or how do I pull this head so I can reverse it?