Steering Gear Box Replacement Help/Ideas?

[RobG]

I have had my steering gear rebuilt 2 years ago and it still is acting up.  The steering wheel pulls hard left and the fluid boils in the pump. 

There has to be blockage in the gear box.  Can I replace another steering box from another model - say a power steering box from a 1985 Dodge 4x4 truck?  Or, what other box can I drop in?

[Chryco Psycho]

is the valve on the top of the steering box centered to stop it pulling ?

[RobG]

is the valve on the top of the steering box centered to stop it pulling ?

I have fussed with this valve many times.  I am ready to throw in the towel and get something else to use.