Power steering hard, need more assist
05-24-2005, 07:53 AM
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Power steering hard, need more assist
I am having some issues with my power steering. It feels like it takes more effort from me to turn the wheel than it used to. I have a new power steering control valve that i installed last year. I know this wasn't the problem but there was excessive play in the joint that attaches to the pitman arm. I have noticed that it has been getting progressively worse. I only put about 3000 miles on a year. I am thinking either the PS cylinder or the PS pump. The cylinder moved fine when I was adjusting the control valve, there was some air trapped in the system that made the adjustment tricky as I would get it all adjusted ,get the car on the ground and the it would deciede to pin the wheel one way or the other that I could not move the wheel. I think when this happened something may have been damaged. As I said before the power steering has been getting worse. I am looking for some Ideas. I did try the old control valve just to see if it made a difference but nothing changed ( as I suspected). i would greatly appreciate any help, Thanks.
05-24-2005, 08:37 AM
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Since you have installed your original control valve and the assist level still seems to be too high, I am thinking that your problem must be pump related. However, it isn't the pressure being developed by the pump, it is the flow from the pump that might be lacking.
If you don't have sufficient flow, you will have to turn your steering wheel further in order to open your control valve ports further in order to supply sufficient oil to one side or the other of your assist cylinder piston. The valve just won't be responsive because of the lack of flow. Your steering will feel heavier.
Do you notice that your steering effort becomes less if you rev your engine to 1500 rpms? The Saginaw pump goes into flow control at about 1500 pump rpms, so faster engine rpms shouldn't make any difference.
This means that no matter how much faster the pump rotates it will only put out X amount of oil to the control valve. Since the pump is a positive displacement device, excess oil (after 1500 rpms) is diverted internally inside the pump.
Here is one thing to try. Remove the power steering pressure hose and unscrew the discharge fitting from the back of the pump. Take a screwdriver and press on the control valve that is right inside the pump behind the fitting. You should be able to press it into the bore against a light spring. It should slide freely. If it feels sticky, that could be the reason why your pump is not putting out sufficient flow.
If you take the control valve out of the bore, you should notice that the end that rests against the spring has a hex shape and a fine filter screen. Make sure that the valve is installed in the correct orientation.
Hope this helps,
Jim
If you don't have sufficient flow, you will have to turn your steering wheel further in order to open your control valve ports further in order to supply sufficient oil to one side or the other of your assist cylinder piston. The valve just won't be responsive because of the lack of flow. Your steering will feel heavier.
Do you notice that your steering effort becomes less if you rev your engine to 1500 rpms? The Saginaw pump goes into flow control at about 1500 pump rpms, so faster engine rpms shouldn't make any difference.
This means that no matter how much faster the pump rotates it will only put out X amount of oil to the control valve. Since the pump is a positive displacement device, excess oil (after 1500 rpms) is diverted internally inside the pump.
Here is one thing to try. Remove the power steering pressure hose and unscrew the discharge fitting from the back of the pump. Take a screwdriver and press on the control valve that is right inside the pump behind the fitting. You should be able to press it into the bore against a light spring. It should slide freely. If it feels sticky, that could be the reason why your pump is not putting out sufficient flow.
If you take the control valve out of the bore, you should notice that the end that rests against the spring has a hex shape and a fine filter screen. Make sure that the valve is installed in the correct orientation.
Hope this helps,
Jim
05-24-2005, 10:23 AM
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The steering is hard at all RPMs. It doesn't matter how slow or hast I am going. As far as I know it is the original pump and the car has over 100,000 miles on it.
When you are talking about the control valve are you refering to external power steering control valve or the valve in the power steering pump?
The power steering cylinder piston seems to push out an pull in ok but I don't know it it is weak. It just feels like there is little or no power assist.
When you are talking about the control valve are you refering to external power steering control valve or the valve in the power steering pump?
The power steering cylinder piston seems to push out an pull in ok but I don't know it it is weak. It just feels like there is little or no power assist.
05-24-2005, 11:04 AM
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The valve inside the pump, right behind the discharge fitting. I should have called it the pump flow control valve.
The reason I say the pump is most likely the culprit is that when you reinstalled your original control valve on the linkage, you had the same high effort as you were experiencing with the new control valve.
The reason I say the pump is most likely the culprit is that when you reinstalled your original control valve on the linkage, you had the same high effort as you were experiencing with the new control valve.
