This concerns Kenmore Progressive vacuum

This concerns Kenmore Progressive upright vacuum 21637115700 part 23 2CKG352000, the belt driven brush bar. I had to take it out for some serious cleaning and it expanded in length about a quarter inch as it is supposed to, I guess. How do I collapse it back so I can re-attach the belt and brush? Thank you...
It was suggested that I try twisting or pushing end to end to which I replied: I had tried both of those suggestions before I went online looking for help because it seemed it was the logical thing to do. This thing will NOT twist ( I went so far as holding it in a vise and using vise grips to try to twist the end section) Does it matter which direction (clockwise or counter clockwise) it is turned? And is there some kind of tab-slot that is supposed to be aligned on the belt drive wheel? I have put as much pressure on it end to end as I can, maybe it's not enough. It seems frozen. Thanks again
Les.. Is there anyone out there who is familiar with this specific model? It was turning fine before I took it off to clean around and behind it. It was pulling lots of air through the hose but not through the floor module ( lots of pet hair). I can't tell if there is a slot and tab that needs to be lined up and if there is, nothing will turn anyway.
Thanks