Mechanics rarely get involved with repairing or adjusting rack and pinion assemblies. The adjustments are too critical and rebuilt replacements are too inexpensive to make repairs feasible. Besides, you know it didn't come that way from the factory. That means something is changing and that is due to loose or worn parts. Those things have to be diagnosed and repaired first.
There's a torsion rod in the spool valve that you have to twist to open a port that allows pressurized fluid to flow and push on the power piston. That's what sets the tension you're referring to. The thickness and stiffness of that rod isn't going to change. That leaves wear in the valve assembly which is another reason to replace the entire rack assembly. The pump is not the cause of this problem. Even if debris blocks the pressure relief valve and fluid pressure goes too high, the spool valve still operates properly. You open it by turning the steering wheel and the movement of the rack and wheels closes it again. Higher pressure will make that occur faster, not easier.
The only other thing that causes light steering is insufficient "caster". That is one of the three basic alignment angles but it's usually not adjustable on front-wheel-drive cars. Higher caster makes a car more stable at highway speeds, with less steering wander, but it makes it harder to turn the steering wheel. Power steering assist was added to overcome that hard steering. If something happened to your car to lower caster, typically crash repair, the steering will turn too easily.
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Thursday, April 11th, 2013 AT 1:44 PM
