It is common for the shaft to separate from the support on KA's.  I'd suggest a new wash arm support rather than trying to use an epoxy to hold the old shaft in place.  Plus, I've also heard recommendations from others on this board that the plastic bearings tend to wear better on the wash arm than the original bronze bearing units.

Great save, BTW!  Love the original literature and sales receipt!

http://www.ebay.com/itm/KitchenAid-Dishw...

You can differently epoxy the SS shaft back in place, I have done this many times over the years on KA WASs.

There should be 3/8" space from the Bakelite top of the WAS to the bottom of the bronze support, I measured a new one that I have on hand.

Both my 15 and my 20 came to me in a "rode hard and put away wet" condition. Needless to say the Wash Arm Supports were really shot so I did repairs on both and used them while waiting for a new one to appear on eBay or through one of the generous folks on this site.

In both cases I used a Marine Grade Epoxy based on SteveT's recommendation. I'm not sure it would be a solution for a machine I'd use every day but certainly worked well as a temporary solution. 

I used a broken popsicle stick to hold it in place while the epoxy cured.  Not very pretty but it worked.  There were cracks on the WAS for the 15 so I put a little glue on those too.

My Father used to take me to Miron Lumber in Kingston(we might have been there on the day that invoice was written up); while he bought wood and nails for his never ending projects, I got to spend time in their appliance department looking at Hotpoint washers and KitchenAid dishwashers. Great place, great town.