Hi.
Swapping the MK1 rack (photo 1)  for a reconditioned MK2 item with green tie rods to suit my Capri steering arms.
The MK1 spline and Mk2 spline both 28 tooth. But the MK2 has a keyway in the coupling (photo 2)
 
The MK1 steering column has a flat section (photo 3)
What's the proper way to put all this back together? Does the flat side of column have to line up with the keyway on coupling?
Thanks

 

 

 

Remove the bolt from the sleave, so it can slide into it. I have something here that might help.

Align the flat on the steering shaft to centre with the slot in the outer part of the splined coupling.
The idea is that when the locking bolt is tightened the slot partly closes up so the outer spline locks into the spline on the steering shaft with no movement.
The flat provides a small amount of clearance to enable the splines to properly lock together.