I am trying to convert my 68 to power steering.  I am using rebuilt parts I bought from Mustang Masters on eBay. I have everything installed - actually went in pretty easily - except for the 'crush nuts'.  But, when I start the engine, the steering wheel pulses like crazy and tries to turn to the right and the v belt starts slipping on the pump.

I can not seem to figure out what is wrong.  Any ideas?  

Did you bleed the system?( 20 turns left to right without the engine running with fluid in the pump and put the return line in a can to catch the fluid) after the bleed, hook up the return line and again without the engine running trun left to right a few times ( I use 10)).
If it's still there, you have a malfunction.  

Thank you very much.  I thought I needed to bleed it - but you are the first with specific instructions!

Now I definitely have power to the system.  But .. the system now moves from stop to stop on its own.  In fact, if I didn't slow it down it would probably damage something.  I think I read about a centering valve - does this need to be adjusted or is ther something else going on?

Thanks ...  

There is an in-car adjustment that sets the control valve centering spring. Remove the cap from the end of the control valve. Tighten the adjustment nut snug (but not to tight) back off 1/4 turn.  This should set the preload to about 12lbs going each direction on the steering wheel.  

Thanks.  I did that and the system still drives the steering wheel from lock to lock - and I mean it turns it HARD.

Anything else that might cause this?  

Start the car and let it idle.  Turn the wheel from lock to lock several times.  That will force any air in the system into the reservoir.  

Thanks to the folks at Mustang Ranch in San Jose, I found out that the cause of my problem was the fact that the hoses from the control valve to the ram were were reversed.  Once I changed that (which is not an easy task because the hoses are a tad bit too long) the steering works much better - although it is still pretty hard at idle.  

Thanks for the follow-up, it's nice to hear that you have it solved. You realize that the Mustang power steering is more of a power assist system and the steering ratio is the same whether or not it's manual or PS. You're turning the gearbox which cranks the pitman arm which moves the draglink and steering ram. After a small delay the ram's control valve biases as a result of the RAM offset and ports fluid in assistance.  

Is the 66 Mustang factory power steering designed to return from a turn like a new car? When I come out of a turn I pretty much have to spin the wheel back to straight. Thanks, Just0610  

I am about to rebuild the steering drop arm in a 68 coupe (power steering) ie control valve as there is too much play.  I have  a rebuild kit including O rings.

Does anyone have any tips and traps before I start.  

I haven't driven mine in a couple of years now due to a complete restore in progress.  As I recall, all it does it make it easier to turn. It is not like a modern recirculating ball or R&P system.