It is done in the outlet valve on the pump. On this one the engineers did their homework.
The valve senses the pressure after the pump, when the steering is idle they run a set pressure from 80 to 150 psi and maintain that. Recirculating ball and rack systems will be at either extreme there. If you ever get to look at the schematic for a hydraulic fuse it may help make sense how this is done.
This low pressure is what controls the on center feel of the steering. From this setting the pressure can ramp up to the peak pressure to help steer the vehicle. Most all of this is done in this valve on these steering systems.
The American designed systems do much of the flow control in the steering box, this being part of the reason American PS pumps do not work on the Japanese steering units.
What this means to a driver, when driving with the American style steering there is quite a difference in steering effort with the engine at idle as opposed to revving at 2000 rpm. In many of the Japanese vehicles there is little change.

Well, we here at Mickey Mouse Inc. <img src="/forums/images/graemlins/smile.gif" alt="" /> figured out a few things in the last couple days! There are NO Mitsu anything in the wreckers within 200 miles! so I have picked up pieces and pumps from Nissans, Dodge colt, and Mazdas (same pumps, but all V-pulleys!)

The innards of the pumps are basically the same. The stator in the Ford pump is adujstable by resetting it on the pins inside. (havent checked a Mitsu pump yet, but I now have 3 extras!) This raises or lowers the pressure. D50 pump puts out about 600 psi. I found this out "AFTER" I cut the pulley off the Ranger pump and just welded it to the stock 2.6 pump pulley <img src="/forums/images/graemlins/scared.gif" alt="" /> I also welded the 2.6 bracket to the Ranger. <img src="/forums/images/graemlins/rolleyes.gif" alt="" />

Heres the option list: (Hardest to easiest)
-Reset Ford pump stator, but have to fab line connections.
-Find pulley for 2.6 pump, and redrill Ford mounting brkt.
-Find Nissan or Mazda pump, (holes line up to brkt) Still need pulley.
-As Old Colt said, get a pump from a V6 (although unsure of mounting and lines)
-ChrisJ has the easiest and best idea (albeit expensive) AGR builds a great pump and box setups, (availability?).
-Tom Allen at PSC Motorsports (Performance Steering Components and original owner of AGR!) in Texas, sells or will build ANYTHING! Also has pulleys, brackets, lines etc.

I tend to experiment A LOT! Most things I try on a temporary basis (unless, of course, it works!) I grew up on a farm 80 miles from nowhere, so I'm used to "making do with what I have".

I know the Mazda pump should be compatable. Can the outlet valve from the 2.6 pump fit any of the others? There are a few different sizes on the OD of the valve.

Dodge caravans, Lebarons, Eclipses, Diamantes, and the like all have the same pump with serpentine. I know, as I searched high & low for one with a V pulley for my Raider & could not find one at the time.

Ed

OldColt-Yes, the outlet fits from one pump to another. I have 2 off of Dodges, 1 Nissan, 1 Mazda and all interchange. The outlet line fittings are all different, 2 banjo, and 2 different sizes of internal flares. The Ranger one doesn't interchange at all (threads and valve are too big).

The 15 Caravans I looked at all had V-pulleys. Some of the later ones had serpentines on the rest of the drives, but not on the pump. The pumps were all the integral tank types with a large V-pulley.

Yeah, just wandered around the junkyard for about an hour looking for some stuff I may be able to work with, but no luck. The later model v6 stuff which may use a serpentine pulley also appears to be a different pump. So finding a v6 pump with a serpentine pulley and making a new bracket/possibly hoses or using the 2.6 pump and fabbing a new pulley and bracket look like my two options right now.....

If you can get a serpentine pulley from another pump and swap by pressing them might help.
Be careful pressing the since the pumps have sintered parts in them and can be broken.

Is this why mine steers so good but leaks fluid?

Hmm I don't know, but mine would get so hot, that it would boil the PS fluid.

how did you get around the boiling before the SAS?