Once you have the nut off, being careful with the special internal-tooth tab washer that costs $4 if you break the internal tooth off,
the spindle should drop right down with some soft faced hammer persuasion. make sure the woodruff key is out of the shaft. That is the only thing I can think of to hang it up. In (New) manuals there is a pdf for RC1 rotary cutters and a section with all the parts including an exploded view of the spindle. If it is too big to download, send me a PM with your email address and I will cut out that section and email it to you.