78 Bronco steering box
 

Hi to all
I just recently bought a 78 Bronco to restore. The previous owner has had the truck for 25 years and was only the second owner. The truck has sat for 12 years, mostly outsite.
The steering seems to be frozen. All of the linkage components appear to have been replaced at one time. Drag link, tie rod ends, steering stablizer. I put the front on blocks and took the wheels off and had someone turn the wheel back and forth. I do not see any signs of binding. The power steering unit appears to be working and has the correct level of fluid. Is it possible the box has frozen due to sitting in the same spot for years? The more I keep working the wheel back and forth the better it gets. Is it possible to grease the internal gears? or should I just start with a reman box?
Any help would be appreciated
Thanks

there is a pressure regulator under the pressure hose where it screws into pump. Remove hose, remove fitting that screws into pump, careful there is a spring behind the valve. Possibly the valve is stuck.Once you get fitting off if valve is stuck you might have to get a magnet or something to get it loose. If you remove pump and put on bench it is easier to work with. After sitting that long it wouldn't hurt to clean out the fluid in the pump.