torsion bars

Take the assembled stack and either tape them together or put an elastic around them. Also, beveling the edges makes it easier to install.

I've found that a small rubber band to hold them in place seems to work better than taping them (although my tape problem might have been that I used too much of it!)

 

Put a bright light into the end of the torsion tube to see the orientation of the hole in the center donut.  It's not round - it'll look just like the end of the leaf stack-up on the torsion bar.  Remember how it's headed for when you insert the bar stack.

 

Slip the band over the end and position about an inch from the end so it'll hold the stack together when it enters the center donut deep inside the tube.  

 

Once engaged (you'll feel it, and can see if any of the leaves get pushed out of position) just tap on the far end with a block of wood until the ends are about equally protruding and you're done.

+1 to everything Gordon said. The only thing to add is that I found that if I angled the stack one way or another, the stack tends to find it's way home easier.
Keep at it. You will get it.

Ted