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Weeping Octopus

James T

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The power steering control valve on my '77 is leaking. The fluid steadily drips out of the end cap even while the car is sitting still. About a 1/4 cup in a few days time. I installed new seals on the spool valve a couple of years ago and while that seemed to reduce the leak for some time, it's now back to it's full flow. I inspected the spool valve closely, and it did not seem damaged or corroded to me. I did not find any foreign material in the control valve, and it seemed smooth inside the housing bore so I did not hone the housing when replacing the seals. Have only driven a couple thousand miles at most since replacing those seals having followed the kit directions to a T. The car only has 58K miles on it, and has always been garaged. It steers beautifully. (Well, as beautifully as this ancient design can steer.) I also have replaced the power steering pump and installed new fluid. Not related to the leak, just FYI.

Refer to this description with diagram - http://www.stangerssite.com/HowItWorksControlValve.html

So, my first question is, should I attempt to replace the spool valve seals once again this time honing the housing cylinder bore? Is there another method/trick to curing this leak myself? Or, is a rebuld the only way to eliminate it? I spoke with Dan at Nostalgic, and he'll rebuild it for $225. Problem is, getting the pittman arm off. There's no room to get a puller on it, and using a pickle fork has some risks.

Last question - if you have had your's rebuilt, how did you remove it, who rebuilt it, how much, and did it finally cure the leak?

Thanks for any/all info.

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Last month, my mechanic pulled from my 78 Avanti II, the Steering box, Pitman Arm and Control valve. Took them about 2 hours to get it out. Not sure what they used. Didn't want to hang around and watch. We packed it all up and shipped to Dan at Nostalgic. He rebuilt the Control Valve for the same price. We thought my worm gear was worn in the box. But, Dan said no. He cleaned up the Pitman and box and reshipped back. No more leak and the "wandering" steering is gone. Not rack and pinion but alot better than it was.

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The controll valve can be resealed without removing the assembly fron the car.

Follow shop manual procedures for dissasembly up to the point of the spool valve seals and you should get an idea of needed steps for job.

Take off cover (2 slotted screws)

Remove 1/2" nut, spacer and spring.

Remove the front cap screws (bolts) leave hoses attached!!!

Slide hoses and spool valve rearwards and note posisition of all parts.

Replace the seals on the spool valve note they have a lip that MUST face the proper direction in order to seal. The lip faces the pressure (they face inward).

Make sure the washers and rubber washers(cushions) are in the correct order as shown in the shop manual.

Slide hose block assembly back over the spool valve.

Install front bolts.

Install rear cushion and washer in the proper order. then the spacer bushing and spring next

Put the 1/2 self locking nut back on and tighten snug.



Reinstall cover and screws

Start engine and check for leaks.

Go on a test drive, If you dont like the sensitivity, remove the rear cover and adjust the nut A TINY BIT at a time (tighter if delayed boost and odd feeling, looser if "darty" and sensitive to bumps.

See it wasn't that hard and you did it yourself!

And you didn't even have to remove any hoses!!!

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Well, that's pretty much the procedure that I followed the last time, Brad, but the leak returned in less than 2,500 miles of driving. So, I guess I can either keep replacing those seals, or bite the bullet and remove the control valve for a rebuild. If I do replace the seals again, I will hone the control valve housing just to be sure it's as smooth as possible. Something has to be causing the seals to deteriorate so quickly.

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I had the same weeping problem on my 85 (why am I not suprised). I sent it to Precision Products in San Antonio TX. They rebuild early Mustang parts. It dosen't leak at all now and the charge including shipping was $106.34. There was a problem, apparently the mustang control valves are assembled with the two castings rotated 180 degrees different that the avanti. Once I figured that out, which took a long time, I removed the two bolts and rotated it 180. Works perfect and no leaks!

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A few years ago I needed to remove the Pitman Arm and Control valve. I loosing up the pitman arm with a fork, which took some time and as I recall, some engineering of the tools, I found I needed to jack up the engine to get the pitman arm off. I removed the motor mount bolt from the drivers side and inserted a short piece of 2x4 between my jack and where the oil pan bolts to the block and jacked it up a few inches. I placed a block between the 2 pieces of the motor mount to support it engine and remover the pitman arm and the control valve. It was not easy or pretty, but it worked.

Hope this helps


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