I refuse to believe that there is no good solution. Full hydro might be it. I want two things: For the orbital to be limited in its ability to keep turning and for my steering to somehow return to center after doing this. If I can implement solutions to those two hurdles then we will be in good shape.
I don't see why we couldn't cram a PSC behind the diff, right where the stock rack goes. Lots of fabrication involved there and I don't know anyone that would ever want to drop the driveline lower, so if anything it would be viable to raise it about 1-2"
@AssBurns
I'm starting to DIG
*Edit: After searching, there is a valve here that will allow your orbital to return to center.*
https://coreswest.com/full-hydro-orbital-steering-control-valve/
Agreed that there is definitely a solution. The issue is finding the solution that has the best performance with the least compromises for your particular situation.
The best for performance would be something like a hydraulic steering rack such as a Fortin, Howe or ProAm rack. Strong, simple, and reliable. Pretty easy to package except for getting creative with the the steering input shaft routing.
The compromise is it's way more expensive.
Full hydro is going to have the overall best strength and easiest to package. Also a decent entry cost even will a full PSC kit. If you get a load reactive, open center orbital valve, you can maintain decent road performance with feedback and centering the steering wheel. Even if you lose pressure with this setup, you can still steer (although not easy) as long as you don't have a leak in the lines. The orbital valve can still provide enough pressure to steer enough to safely get off the road in the case of pump failure. How many of you actually lost a power steering line? I haven't and if you secure the lines properly and get good crimped hoses, you shouldn't have an issue with the lines.
The compromise is there isn't really a failsafe of having mechanical linkage. But in reality this is no different than having a broken drag link or pitman arm failure on a SAS rig.
Saginaw Box/Swing Set + Hydro Assist seems to be a great middle ground. It still provides strong components that have been proven in solid axle rigs for years. Steering box takes way less load with the assist powering you through the rocks n shit. With this you can even get better steering geometry since swingset can follow the arc of the steering arm/spindle to theoretically zero out bump steer (if you design it right). This could be done at a decent cost with junkyard saginaw box and easily available components for swingset steering. Hydro assist would be the most expensive part.
The compromise is packaging. There are more moving parts to stuff under the transmission and mount the saginaw box. This can get more complicated than other options.
Stock steering rack with rack saver + hydro assist. Seems like this could be a good option but I'm still not convinced that the rack could hold up to the abuse even with hydro assist and a rack saver. Between the rack taking the standard abuse and wearing out the seals, or bending the main shaft; or the hydro assist causing undo wear on the rack. The good thing is that even if you blew a line or had pump failure, you would still have the mechanical linkage as a failsafe. I could be over thinking it, but not sure if I want to tackle this project and have it still be a failure down the road.
The compromise is what I mentioned above in my concerns about the stock rack not being able to take abuse.
