Steering clutch control

Thought I knew but I'm not sure. Appears to be a key involved for the clamp which may require the shaft to be pulled up and would probably destroy the
 bushing on the way up. Going down the lower bushing appears to be a smaller diameter and the key might damage the lower housing.
Here's a better cross section view of what's going on.
 [attachment=77189]62318e1ae3bfdfc79fe923b968d4df93[/attachment]

Did some more research on the bushing sizes. The upper bushing has an ID of 1.740" = shaft OD
The lower bushing has an OD of 1.502" = lower housing bore so the shaft is not going to pass going down.
I checked the many applications of the steering booster and none of the Service Manuals show instructions for splined shaft removal.
I suspect original assembly was keyed shaft inserted through the clamp into the bottom housing/bushing and then the upper busing was installed making it a locked in assembly and it was not intended to be a service part.
If the key is in the smaller diameter portion of the shaft (1.254" Dia.) depending on how far the key sticks out it should clear the upper bushing (1.740" ID) and the shaft could be removed by lifting or pressing up but that's certainly going to be a challenge.