I converted my 66 c10 to ps back in 2005. I recently drove the truck and had the steering fail. The alignment pin on the rag joint sheared. After taking the old joint off, I found the steering shaft and the input shaft on the box don't align perfectly. I suppose it could have been that way on the install, but don't remember that....but it was cold out that day!! I'm assuming a little misalignment in the geometry could put a heck of a load on the joint. First, is it possible to correct the alignment some by shimming the box? Second, would a borgeson joint be more forgiving, and how difficult is that install? I think the rebuuilt box I bought was from a 76. Thanks!
Did you shorten the shaft after you installed the power steering unit? That could be the start of your problems.