If you have access to the book Land Rover Series III Reborn check out the chapters on replacing the doors with Defender doors and the one on power steering. On the power steering they work with a kit, but there are lots of pictures and a diagram of the layout.
It covers lots of things reference to restoring a series III and has lots of pictures of the process.
The book uses a lot of Santana parts, but basically they cover taking two trucks and making one basically "new" truck.
Wayne
Wayne
Beautiful downtown Quinton, VA
1982 Series III 88 Country
2001 Disco II, Zebramobile-Sold