This sounds like a centering valve problem
I was reading in the August issue about loose steering. I am restoring a 1964 Mercury Comet Caliente two-door and am currently working on rebuilding the front end. We have replaced both upper control arms, both lower control arms, both inner tie rods, ball joints, tie rod adjusting sleeves, the idler arm, both shock perches and many rubber bushings. The front end was aligned correctly, we were told, and we made sure everything was greased properly.
We now have another problem when driving the car. If you make a left turn and then straighten out to drive straight and then let go of the steering wheel, the car pulls to the left. If you then make a right turn and then straighten out to drive straight and let go of the steering wheel, the car will pull to the right.
You do not have to fight the steering to drive the car but you can never lose sight of the fact that should you ease up on the steering wheel you will either pull right or left. My mechanic says I need a new, what he calls a centering valve or control valve.
After spending lots of dollars I want to be careful on spending any more money for things I do not really need, but I want the car to be safe and correct. Would you advise replacing the centering valve or would there be another cause to consider? Your advice would be most helpful.
Assuming your Caliente has power steering, the centering valve is very likely your problem. You can obtain a kit and rebuild the valve yourself if you want to save a little money, or you can just change out the valve for a new or rebuilt one. The valve works by applying hydraulic counter pressure on the steering system unless the wheels are pointed straight ahead, in which case no pressure is exerted.
If you do decide to rebuild the valve yourself, do so in a clean environment because one tiny bit of grit can ruin hydraulic parts. Take the valve apart systematically, laying the components out in sequence as you proceed. Flush out the valve as well as the power steering system and use only clean new fluid to refill it.
I would then adjust the steering box per the instructions in your shop manual to make sure the steering is tight with no slop but centers easily and automatically. Don’t over-tighten the steering adjustment though, because you could end up with a hump, or hard spot at the center.
If the car were not equipped with power steering I would re-check the camber and caster on the alignment as well. If all of that is set to neutral, the car will tend to wander as well.