[dsraven]

here is a blurb from the hotrodders site by a guy called centreline. maybe it will help.


Someone asked the other day about a problem he was having with his Mustang II rack blowing out seals. He was running a GM pump and a Mustang II IFS power steering rack unit just like everyone else and wasn't sure why he was having the problem or what was causing it.

To begin with the GM pump puts out too much pressure for the Mustang rack. GM power steering pumps operate between 1000 and 1200 psi. Mustang II power racks were only designed to operate between 700 and 800 psi. This difference in pressure requirements can and does cause a couple problems.

First is a very "touchy" feel to the steering at highway speeds. This makes any vehicle a pain to drive for long periods since you can't really relax while driving. You have to pretty much be on top of the car at all times. The second problem is blowing out seals in the Mustang rack. You don't want to see power steering fluid puddling under your car in the driveway but it can and often does happen with this combination.

When he contacted the company that made his Mustang II kit, one of the guys there told him to just "cut" the pressure spring in the back of the pump. This is NOT the right way to lower the pressure of a GM pump. If you cut the spring it's like shooting in the dark. You never know what pressure you'll wind up with because a little taken off the spring can make a lot of difference in the pressure output of the pump. If you cut too much you could wind up with such low pressure it would be like driving with a manual rack. So, how do you correctly solve this problem?

The solution to all this is of course to lower the pressure of the GM pump and there are basically two ways to correctly do this. One is to purchase an Adjustable Power Steering Valve from someone like Heidts . They go for about $125 with all the fittings you'll need and basically mount in the high pressure line and allow you to dial the pressure you want. This method works well but for some people it can be a bit pricey.

The second solution, and the one I recommend, is to pick up a GM Power Steering Pump Flow Valve kit from Borgeson. With this kit you can easily adjust the line pressure in a GM pump to make it compatible with the Mustang II rack. The kit includes simple instructions, shims, and all the parts you'll need to do the job including a tool to hold unit in a vice while installing shims. If you are interested, take a look at page 11 of the Borgeson catalog (there's no picture but that's where its listed). The kit costs less than $30 and takes about 15 minutes to install. Best of all, it reduces the pressure the at the pump and no "add on" in line valve is required so there are less fittings to leak.

So if your Mustang II power steering is making your ride feel a bit skidish on the highway or you're rack is leaking all over your driveway, you now know a couple ways to properly solve the problem.

Centerlin