When looking to raise the front of my 85 Toyota truck for rockcrawling I run into some issues with the steering. It was going to be necessary to either modify the drag link or steering arm drastically and still face issues with bump steer. Furthermore it was going to still be a limit to how much travel the front axle could handle. After looking at many different options it became clear that hydraulic steering was going to be a necessity or at least the best option.
I am currently working on converting the steering now. I ordered a steering unit from ebay and a double ended hydraulic cylinder from a surplus company.
Although there are calculations to figure out how big of a cylinder you need and also which steering control unit to use, I just kind of went by the seat of my pants and guessed about what size would work well and then found the parts that were close to that size and ordered them as cheaply as possible.
The nice thing about a full hydraulic steering system is that all you need to make an axle steer is to run hydraulic hoses. There are no mechanical linkages to the axle. This eliminates bumpsteer problems and many other issues commonly experienced on large 4×4 rigs.