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This section is based on the Bendix-style control valve and ball stud units commonly found on 1958-1980 Ford products. Most of the text is specific to the units found on early Mustangs, Falcons, Fairlanes, Galaxies and their Mercury counterparts, but also generally applies to earlier and later versions also. This style unit was used on Fords with "power assisted" steering where hydraulics connected to the steering linkage was used to help turn the car. This was the system used before integral steering boxes and rack & pinion steering became common in the late 1970's.

Although this style system cannot match the tightness, response or road feel of modern rack & pinion steering, it is still an effective setup that can offer good performance and service. Over the years it has developed a reputaion for looseness and fluid leakage, but those are not flaws in the design itself but due to age, abuse and neglect. A properly built, adjusted and maintained system will provide many thousands of miles of trouble-free operation.

Any new or rebuilt Control Valve & Ball Stud unit should already come adjusted and fully lubricated. Many of the parts inside the control valve itself are continuously bathed in power steering fluid, so there is no need for extra lubrication there. The ball stud area does have a nipple for a grease fitting and can be lubricated as needed. However, the ball stud and bushing moves very little inside the sleeve area so little lubrication is required. What lubricant is installed during the building of the unit is more than enough to last the through the warranty period and beyond. New units should not require any additional lubrication for 10,000 miles or so. Since the ball stud area is fairly small, only a small amount of grease is needed to lubricate the pieces. Usually, no more than one or two full pumps from a standard grease gun is all that is needed.
One mistake that is often made by people installing new or rebuilt units is the tendancy to over-lubricate the ball stud area. Many people will hook up a grease gun to the fitting and pump away until grease starts blowing out around the ball stud. The problem with this is that it is possible to over-fill the ball stud area and impair the operation of the unit. If too much grease is pumped into the ball stud area, it can fill the unit to such an extent that the pieces inside cannot slide and move properly. It is possible to form a "hydraulic lock" inside the ball stud sleeve because there is no room for the parts to move inside because of the excess grease. When this happens the ball stud will not move like it should and actuate the control valve. Usually this causes the steering not to provide power assist when turning in one direction. Over filling the ball stud area is not a warranty problem and easily identified. Go easy on the grease - a little bit goes a long way.

One of the most common complaints comes when a customer takes the car in for a front end alignment after installing a control valve and ball stud assembly. The alignment shop will often say that there is too much play and movement in the ball stud and therefore they cannot properly align the car. They will even show the customer the car on the rack and how the ball stud moves back and forth in the sleeve without moving the linkage. The problem with this is that they do not have the engine running and the power system operating. When the engine isn't running and the system isn't under pressure, there is some play in the ball stud. This is normal. However, when the system is powered up, the play disappears because the hydraulic action moves the linkage as it is supposed to. Remember, the ball stud does not move the linkage - it actuates the control valve and pressure system. It is the power cylinder that moves the linkage as it gets pressurized fluid from the control valve.
If the alignment shop is not knowledable enough to know how the power-assist system operates and align it accordingly, take the car to someone who does. Generally, if the alignment mechanic is younger than the car he is working on, he hasn't a clue how to align it. Many alignment people never see anything that isn't rack & pinion, so they have no business trying to set up your classic car.

New and rebuilt control valves should already come adjusted when you get them and require no further adjustment. The only accessible adustment is found under the aluminum end cap on the far end of the valve. This consists of a nut on a threaded rod and controls the centering of the spool valve inside the valve housing. Many people think this nut should be turned down tight, like most nuts are supposed to be. However, this is an adjustment and is not supposed to be just tightened down.
This adjustment is misunderstood and played with to supposedly correct all sorts of problems associated with the control valve. However, all this adjustment does is center the spool in the housing. If it is misadjusted, the steering tends to provide power assist more in one direction than the other. When severely misadjusted, the wheels may actually turn one direction by themselves due to the imbalance. For this reason it is important not to tamper with this adjustment unless you know how to do it properly.
This adjustment has nothing to do with the tightness or looseness of the ball stud, the play in the valve assembly or the sensitivity of the system. Playing with the adjustment of the centering spring will probably violate your warranty. If you think that some adjustment needs to be made to your valve, always contact the supplier or rebuilder before proceding.

These are the two short hoses that run from the control valve to the power cylinder. Pressurized fluid from the valve actuates the cylinder which then moves the steering linkage by pushing or pulling against its mount on the frame of the car. These hoses must connect to valve and cylinder is a specific way to operate properly. It can be difficult to know just how to hook the hoses up properly, especially when working under the car.
When these hoses are "crossed" or hooked up wrong, it usually causes one of two things to happen. Sometimes, when the car is first started up and the system pressurized, the steering wheel will turn and power in one direction but cannot be turned the other way until the engine is shut off. More commonly, the steering wheel can start turning rapidly back and forth, lock to lock, with such violent force that you could be injured trying to stop it. Because of the damage that can be done to the control valve itself, not to mention physical injury to yourself, always be sure you have the two short hoses connected properly before starting the car. And never reach in the drivers window and through the steering wheel to start the car. It could literally break your arm. Go to this page to see a diagram and description of how to properly align and install the short hoses from the control valve to the power cylinder.

Check your owners manual or shop manual for the fluid that is supposed to be used in your car. In most cases, this is Type "F" Automatic Transmission Fluid. This is what the engineers who designed the system recommended and built the system around. The seals, gaskets and rubbing surfaces were all designed for Type F fluid. Do not use auto parts store generic power steering fluid in your system. It may say on the bottle that it is compatible with all systems, but it isn't the specific fluid recommended by Ford for your car. It often contains some form of alcohol which is used to swell and soften old seals to stop them from leaking. You don't need additives in a system with new seals and parts. Also, it tends to thin out under hot operating conditions, which can cause the system to lose pressure and respond poorly. Type F Fluid is cheaper than special power steering fluid and it is what your system was designed to use. Failure to use Type F Fluid may void the warranty on your new parts, particularly the power steering pump.

The most common complaint after installing a new or rebuild control valve is leakage of power steering fluid. It is sometimes difficult to tell just where the leak is coming from because fluid gets blown around under the car and on the parts. It is important to find out EXACTLY where the leak originates in order to fix it. It may be necessary to clean the area thoroughly and then idle the car and turn the wheel while looking underneath to see where the leak starts.
There is not supposed to be any fluid under the aluminum end cap or in the ball stud area itself. Fluid leaking from these areas indicate that one of the spool end seals is at fault and leaking into those areas. Unless there was a problem during installation that might cause this, or someone has modified the valve, this would normally be a warranty problem. Make sure of the source of the leak before contacting your supplier or rebuilder.
By far, the most common area for a fluid leak to occur is at a hose fitting. Fluid from a hose fitting can run or drip to other areas of the valve, leading you to think some other area is leaking, so be sure of the source. There are several reasons why leaks around the hose fittings can occur.

1 ) Over-tightened fittings. People tend to tighten down things as tight as they can get them in the attempt to avoid leaks, but the fittings are easily
deformed by over-tightening. When everything is right, fittings only need to be good and snug to keep from leaking.
2 ) Damaged hose tube seats. Inside the ports of the control valve are soft, tapered aluminum seats that the hose tube end seals against. These are
easily damaged by over-tightening of the fittings, twisting of the hoses and damaged hose tube ends.
3 ) Damaged hose end flares. If the hoses are used, the ends may be out of round, warped or burred from previous use.

It is best to install new hoses on new or rebuild control valves, or at least check the hose ends to make sure the fittings are not deformed and that the flare is not damaged in any way. Sometimes a seeping fitting can be fixed by loosening the fitting, turning the hose end a slight bit and then re-tightening. This gives the hose end a little bit different area to seat against where it may seal better.

It is important to understand that the threads of the fittings do not seal the hose to the valve. The threads on the hoses are not tapered "pipe" style threads and are not designed to seal. It is the compression of the flare on the hose end against the seat inside the valve port where the sealing occurs. For this reason, it is useless to use sealers or Teflon tape on fitting threads when installing hoses. Use of sealers or Teflon tape may contaminate the system.

Another thing to be aware of is most rebuild kits do not come with new hose seats and not all rebuilders install new seats during a rebuild, even though it is not a true rebuild without replacing them. Some rebuilders leave the old grooved seats in the valve where most people never notice them or they get covered up when the valve is painted. If the seats are old and damaged from previous use, even new hoses and proper tightening are not going to seal the hose up.

Many Control Valve & Ball Stud units screw onto the end of the centerlink or a centerlink extention. All units from 1967 are of this design. There is a specific distance that the assembly is supposed to be threaded onto the centerlink for proper alignment with the rest of the linkage. Never assume that screwing the new assembly onto the centerlink the same amount as the old one was screwed on is correct. A previous owner or mechanic may have installed it wrong or your new assembly may be a slightly different length than the one it replaces. Check the information that comes with your control valve assembly to see what the correct position is on the centerlink. If the instructions do not cover your car year or model, refer to the proper shop manual for directions.
There is a hole in the threads of the centerlink for a roll pin to go into. This roll pin locates the ball stud sleeve in the correct orientation on the end of the centerlink. Make sure after you have the unit threaded onto the centerlink the correct distance, that you line up the hole with the slit in the ball stud sleeve. Install the roll pin and then install and tighten the clamp.

Control valves used before 1968 used a 1/4" size pressure port. Those built from 1968 and on used a 5/16" port. Since most control valves operate the same, it is not unusual to mix the housings due to availability. When this is done it is best to use a pressure hose with the proper fitting to fit the valve. When this isn't possible, a brass adapter can be used to adapt the hose fitting to the port, though it is not recommended.
It is important that the proper style fitting is used to prevent damage to the control valve port and housing. Since the hoses use flared ends to seal, the adapter must use flared areas to match the housing. Do not use a pipe thread fitting. A pipe thread fitting has increasingly larger diameter threads to help it seal when tightened down. The ports on the control valve housing are not designed for this type of seal and do not have the strength of extra metal around the ports to allow this. Using a pipe thread fitting in a control valve housing will cause the hole to expand and the threads and housing to crack. Only use the correct taper seat style fitting in a control valve.
Keep in mind that using a brass fitting adapter will alter the length and fit of the pressure designed to fit the valve. This may cause interference of the metal portion of the hose with the ball stud, the pitman arm or other linkage parts.