Brothers of The Benz,
Having spent some time with Saginaw Steering of General Motors;
I could elaborate on the excellent features of the straight ahead high center that is set on the ciculating balls and nut or the amount or thrust required to get power assist; but you didn't ask how to build one.
The prime reason G.M. made the change over was COST. A diecast aluminum housing and circular seals on the right and left chambers verus the ferrious casting in the old units and the many support componentrs.
This was right in line with front wheel tail draggers. The steering performance just fit right in with the new front wheels drive auto.
Just count the components from one to the other.
Cost Reduction with shorter life is what the rack and pinion brought to the party; the influence of the imports.
My W-124030 is still on the original settings with no leaks, excellent feel of the road with rumble effect not present. 15 years ans 188,000 miles.
Happy Trails Beep Beep from The Spiderman in Houston!!!