Surprisingly, it does take a little more pressure from the power steering pump to turn left than to turn right. It is because there is more surface area inside the assist cylinder as it retracts (turning right) than when it extends (turning left). So if your pump is marginal in terms of putting out maximum pressure, you might notice a difference turning one direction as compared to the other. Also, since the pump has to work harder in one direction than the other, if you have marginal belt slippage, it could slip more when turning one direction than the other.

When you do run out of pressure assist from the pump, it typically does feel as if you have lost all power assist in that direction.

The highest pressure from the pump is required with the car stopped, brakes applied, and the tires on a smooth concrete surface. Modern wider tires may require somewhat higher pump pressures to steer your car as compared to the skinny (smaller footprint) OEM tires.

So first make sure that you have correct tension on your power steering belt. (Make sure that the belt isn't glazed or badly worn.)

Also are you really sure that all the air is out of your system? And are you really sure that you have balanced the control valve correctly?

Only if you are sure of the above questions would I attempt to go further:
You might be able to perform the following without taking the pump out of the car. However, it will be a lot easier working on the pump if it is out.

I would remove the pressure line from the back of the pump. Remove the discharge fitting. Reach inside the cavity and press on the flow control valve that is behind the discharge fitting. The valve should slide easily against a spring in the bore and not be sticky. If it is sticky that could be the cause of your problem.

Use a small magnet and remove it from the pump. Check for dings and/or heavy varnish type deposits on the valve that might cause it to stick.

If you are sure that it slides easily than I have one more thing to try. Clamp the valve between two pieces of plastic or wood. (You do not want to damage the OD of the valve. It has a very precision diameter.) Now unscrew the small screw with a screen on the back side of the valve. There should be two shims under the head of the screw. (The more shims, the lower the pressure setting.) Just remove one of the shims. These shims control the maximum pressure that the pump can generate. The original pressure setting was 950 to 1100 pressure max. You do not want to raise the pressure setting any higher than absolutely necessary.

The power steering hoses in your car were only rated for 1100 psi max. Going much above that pressure level will reduce the life of the hoses.

Reassemble the spring, then insert the valve (with the screen nut first), then screw the discharge fitting into the back of the pump. Assemble the pump to the engine. Refill and deaireate the system as described above.

See if the higher relief pressure makes a difference.

Jim

 

Its funny to listen as some people back their car out of spaces while standing on the brake pedal.
The steering knuckles popping and creaking and the poor old pump screaming-HELP ME !!!

(I have tried to explain to my elderly neighbor how hard standing on the brake is on the steering system but she doesn't seem to grasp it,last year she blew a ps belt off in the middle of the street,she still doesn't get it. )

 

Thanks Jim I will give the above a try, also if the
control valve is not balanced correctly would the car
track down the road straight, mine goes real straight

 

I suspect that the car might still track straight even thought the valve was not balanced. But I don't have any actual evidence one way or the other.
Jim

 

obama fan ? Not a chance

 

I recently had a corvette in my shop doing something like yours.It would only turn in one direction. Turns out the guy who replaced the control valve also replaced the pitman arm but he installed one from a non ps car. They look very much the same, but will bind on the steering rod if mixed up.