I noticed that I have a slow leak in the powering steering valve on my 77.  I was told not to mess with trying to rebuild it with a kit.  How difficult is it to replace the whole power steering valve unit.  Are there any special tools that I would need to do this.  Thank you for all of your help, I appreciate it!

IF I can ever get the software to load, there will be an in-depth article in Shark Bytes about converting a 71 Shark from standard to power steering and refreshing an 80 model.  Hope to have it going later this week. 

These articles should help.

We didn't try to rebuild the valve, just replaced hoses and pump on the refresh.

Which valve is leaking, the control valve (small one) or the hydraulic assist cylinder?

It is the small one, the control valve.  I hope that you are able to post those articles you were talking about.  That would really help me.  I know once you replace the valve that there is some adjusting you have to do with the bolt that I believe adjusts the spring inside the valve.  Not too sure what I may be getting into!  Thanks for your response!

This may seem like a silly suggestion(who, ME?) but the factory service manual(s) will cover this. It shows how to disassemble/rebuilt the control valve.
Or...the valves can be rebuilt, but they do take a little attention to detail in doing it. The only real problems you might have is getting the adjustment done without snapping your arm off when you start the car!(It's happened)
In order to simply replace the valve with a new/reman one, you need to note how many turns it takes to get it off of the drag-link/linkage. The valve screws onto the drag-link. And of course, it is attached to the steering gear box.
The adjustment after installing it is to have the front of the car in the air(on stands). Start the car, taking care NOT to stick your arm thru the steering wheel.(This is VERY important!!) Once the engine is running, the wheels will normally move to one side or the other on their own. If the valve is really far off on the adjustment, when you start the car, it will slam the steering wheel to one side. THIS is why you NEVER want to start the car with your hands thru the steering wheel, or hold on to the steering wheel when you start it.(after replacing the control valve)
On the end of the control valve is a metal cap. That cap needs to be removed before starting the car. Under that cap is the slotted adjustment "screw". You turn this screw in both directions, until the wheels are centered. Turning the adjustment one way will move the wheels to the right, turning the other direction will move them to the left. When adjusted properly, the wheels will stay centered by themselves. Once you have that done, turn the car off, and replace the cap on the end of the valve. Put the car on the ground, check the fluid level in the P/S pump, and drive it like ya stole it!Adams' Apple2007-03-06 11:14:38

And that, boys and girls, is the article in a nutshell.  No need to post it now, no sir, uh unh, no way.

Thanks a ton!   I will be starting this project shortly

When I got my kit to rebuild my leaky valve, it said to disconnect the ram from the drag link.  This stops the need to be careful about the steering wheel.  Then you adjust it for no movement etc.  The instructions tell you what to do.  The hardest part was splitting the valve connection from the pittman arm.  The rest is easy.