Power-assisted steering
dbfarr, since few people have looked into the early Mustang power-assisted steering like you have, I have a few questions and observations. I'm still learning about this system myself.
You mention that there is inherently 3 or so inches of slack designed into the control valve for it to sense movement. Could you explain this in more detail? You must be talking about movement at the steering wheel because there is physically only about a half inch of travel possible in a properly assembled and adjusted valve assembly. The ball stud only has a few hundredths of an inch of spring slack before it moves the spool inside the valve and starts hydraulic turning action.
May I ask who rebuilt your control valve or where you purchased it from?
A properly rebuilt control valve assembly should have no burrs or problems that causes the system to pull one way over the other. This is usually an adjustment problem.
Although more people have had favorable results from new reproduction control valves than not, they do have their own problems. Both the Stainless Steel Brake and Flaming River valves are built to tighter tolerances and are more likely to bind or stick. The SSBC valve has several parts that are designed differently from the original Bendix. These are not improvements and often cause problems. Because of this, they do not consider their own valve to be rebuildable. The Flaming River valve also is built differently than the original. It does not even use a real seal on both ends of the spool valve, just a rubber o'ring. A round o'ring is often used to seal, but not usually to a sliding surface. The seal surface of the spool valve is extremely rough compared to the original design, so I don't know how this is supposed to hold up over time. Personally, I do not think either repro valve is a superior or even an equal quality design to the original Bendix.
"Crossed" cylinder hoses. If you look at a 65/66 Mustang, the hoses from valve to cylinder run quite straight and parallel. Top of valve to top of cylinder, bottom to bottom. The drivers side tie rod ends on this model are curved to keep them from hitting the control valve under certain conditions. However, it is common for the adjusting sleeve (when improperly positioned) to have its bolts still hit the valve housing or end cap.
In 1967 Ford went to the use of straight tie rods. To give them more clearance from the control valve, Ford "twisted" the valve backwards in relation to the centerlink. That means that the cylinder hose ports on the valve housing run more front-to-back while the cylinder ports are more up-and-down. This is why the 1967 and later Fords look like the hoses are crossed. I don't think this was a "hangover" design, just a consequence of a modification needed because of the tie rod change.
The Saginaw recirculating-ball steering box has been around since the late 50's. It was "state of the art" at the time. Since this is a General Motors design, there is really no difference between the basic design of a Mustang box over a Corvette box. The Mustang box is the same manual or power except occasionally the internal ratios are adjustments are slightly different. It is not a perfect design, but a pretty good one. I thought it strange that the article you linked to made a big deal about Flaming River improving their boxes by using needle bearings to support the sector shaft instead of bushings. Ford changed from bushings to needle bearing on the 1963 Falcon, so the Mustang never has the poor bushing design to begin with.
May I ask, who built your steering box or where you purchased it from? A box that had a grinding situation towards one lock is generally a sign that the teeth are worn and require the adjustment nut to drive the sector shaft deep into the teeth on the rack block. Sometimes this causes the sector to drag on the inside of the housing at one end. This may have been your grinding. If so, the gears should have been replaced.
All steering boxes will have some accumulative play, but that your new Flaming River box had almost as much as your old box shows a problem. Most people are happy with their Flaming River box, but I have run across several unhappy users. I have heard that they are made in Argentina, but have not had the chance to take one apart and see for myself. If so, I have seen Argentine reproduction steering box parts and find them of poor quality and design.
I have seen Mustangs with steering linkages under them from other year Mustangs and even Mavericks, Granadas, etc. Since all of these cars use different length centerlinks and tie rods, and different location holes for them, I do not recommend using anything except what Ford originally designed for each model. The differences in steering geometry can't be good.
Though my questions and observations were to dbfarr, I would welcome any comments or questions from any other members of the board. Though I have a lot of Ford factory manuals and literature on the power steering systems, and several years experience in rebuilding them, I find that I often learn something new occasionally if I'm not careful
