I have a TCI Mustang II frontend in my 55. TCI tech documentation says the rack is actually for a 80-84 Thunderbird. I also have a 2000 EFI Explorer 5.0 motor which includes the stock Explorer PS pump. My problem is I have no power assist at idle, but it works fine if I up the RPM's. I read that the Thunderbird rack is capable of handling higher pressure than the actual Mustang II rack, this is how the Chevy guys get around the issue of their pumps putting out too much pressure. I think I am having the opposite problem.
Does anybody know of a pump that will bolt into the 2000 5.0 but has a higher PSI output than that pump?
Thanks
-Pat

 

The pear shaped Saginaw pump will fit most any engine, it was commonly used by all the US manufacturers. Sounds like your pump is bypassing too much. There is likely a ball and spring that controls the bypass, it may have a broken spring or something holding the ball off the seat. Shouldn't be difficult or expensive to find a pump at a U pull yard.

 

This may or may not help, but in regards to the Saginaw steering pump.
Alot of Ford full size vans that had 5.0/5.8 engines used a saginaw pump.
You would need all the bracketry and front engine stuff. timing cover/ waterpump. balancer(maybe) and pulley's. none of it is the same as the 2000 5.0 stuff. Would be a pain just for more pressure, but some food for though.
Good luck!

 

A slipping belt is another possibility.

 

On the back of the saginaw pump, where the pressure line attaches, is the pressure relief valve. After removing the pressure line, the valve unscrews. You may be able to swap the valve for one from a Tbird. I swapped the valve on my pump for the one that was in the saginaw pump on my Jag clip.

 

Just wanted to update the thread on what the problem was. The explorer "C3" pump has a brass insert pressed into the high pressure output port. It is in the port about as far as the threads end. The insert affects flow in some way, how is a mystery to me. This isn't a spring or valve, but more like a plug with a hole in it. I ended up using an adapter fitting to convert to AN hose. The first fitting I used was apparently too long and pushed this insert in further. I got a new fitting and tried pulling the insert back out, but never got it to work right. I finally bit the bullet and picked up a used pump. Of course when I installed it my fuel pump decided it was going to fail at that moment...so after fixing that little issue I fired it up and it worked great right away.

 

I have the '96 Explorer 5.0... I assume it's the same as yours? C3 pump?
I have to figure out my setup using the Jag rack n pinion.
I want to know who makes these pumps? I have a remote res. pump from my '87 Buick Grand National sitting on a shelf. It is very similar to the C3 pump, it had different outlet/inlet locations, but close...
The actual pump case looks identical though.

 

I know what pump you are talking about, but I think the internal porting may be different since the buick pump has one side blocked off. Can you find out what pressure range the Jag rack needs to operate properly? The explorer pump will put out about 800 at idle and around 12-1300 around 2000 rpm.

 

There has got to be someone that can answer that question. I know there are pressure adjustment valves that can be bought, but I don't like the looks of a cobbled up series of one thing plumbed in to take care of another mess. i will see what I can find out and report back. Nice find on your problem, that had to be tough to figure out!

edit: this is some info I found and put it on my word document for notes..It may help someone in the future.

The Ford CII pump (F150-350, Bronco) flows 1.5 gallons/minute at 740 psi. The pressure relief is in the pump and set at 1400 to 1500 psi.

The Ford Saginaw pump (E100-350) flows 1.8 gallons/minute at 620 psi and its relief valve is set at 1350 to 1450 psi.

 

I just found this PDF out there in Cyberspace..

I read about the pump pressure on page 10-139

see what you think. I am not sure of what year JAG it's talking about, but it does mention XJ6 and 12...so I am hopeful this is helpful.

For myself and other Jag users.
http://vintagetest.net/chassis/chis75/V2I7510138.pdf

 

The numbers in that document look promising. I would try it with what you have, it just might work! Again, be careful with what fitting you use on the pump. I did some research and ended up getting mine from Lee Manufacturing in California. Lee Manufacturing Company Sun valley, CA 91352 Steering gears Pumps Reservoirs I called them up and the lady knew exactly what I needed. It was something like 12 bucks shipped. Of course, this will convert you to -6AN.