Replace with a new OEM pump -- if it needs replacing.....Many rebuilds and aftermarkets don't last very long. It's a crap shoot, some do and some don't. An OEM PS pump can go 15+ years, so you get what you pay for.
PS pump gets filled with AT fluid, not PS fluid like some other automobiles. Not sure I know what Simpson is, but if it's not AT fluid, then this might be cause for some of your troubles.
Would be helpful if you could describe "steers hard" in a little more depth. By hard do you mean it requires a good deal of physical effort to turn the steering wheel?
When the PS gear box wears, the steering tends to get "loose" or feel sloppy. By your description, I would say that your PS pump is failing and not providing adequate hydrolic pressure to drive your gear box, hence making your steering feel "hard". Overtightening the adjustment screw on the PS gear box can make it "harder" to turn, but it's more of a binding sensation rather than a constant resistance.
HTH,
-dogboy- '87 FJ60
