Your assumption about steering knuckle leverage is correct.  The tie rod
attachment on the manual-steering knuckles is farther from the ball
joint axis than on the later models with power steering.

I can tell you from daily experience that using a manual steering rack
with power steering knuckles is a lot of work in parking lots.  It works
fine on the highway.  I am in the process of converting my '82 diesel to
power steering for this reason.  I want the larger '86+ brakes.  The
shortest path seems to be to install the entire front suspension from an
  '86+ van.  I'm installing power steering to go along with the brakes.

If you are going the other direction, you'll want the steering knuckles
from a manual-steering van to provide the extra leverage.  I suspect
that VW continued to make manual steering Vanagons after 1985, but I
don't know if they imported them into North America.  If you can't find
manual knuckles that will work with the larger and more powerful '86+
brakes, you'll lose brake performance by swapping the early brakes into
your '86.  You will also need the rod that connects the steering gearbox
to the rack, as they are different lengths for power and manual steering
vans.

--
Michael Snow
1982 Westfalia 1.9TD
http://slowmachine82.blogspot.com/

Dave Arthur wrote:
> I have an �86 Westy, steering rack (power) is suspect, previous owner left
> the pump unhooked due to leakage.
>
> I have a new standard rack, does anyone know the following...
>
> 1. Will it work?
> 2. The steering knuckles are supposedly different between power and standard
> steering. I�m not sure what the difference is.
> 3. The power rack has a universal joint between the rack and the steering
> shaft, the standard steering uses a flex plate.
>
> I�m not sure how drivable the standard rack will be, I suspect the knuckle
> difference may be one of leverage.
>
> Any ideas or comments are welcome.
>
> Dave