If what you have is like mine then there is a clamp screw on top that needs to be released and a pin in the disk at the collet end that needs pulling out. There is a retaining ring at the other end that may need adjustment to stop it binding on the body of the indexer. There are videos on improving the squareness of the Base that may help if you find them.
Martin
BasementShopGuy did the videos I am thinking of.
Edited By Martin Connelly on 31/12/2015 14:31:12