Oh man, Steering problem

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Spenc71

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Ok fellas I have a problem and I know one of you can help me.
I will try to make a long story short. 71 Dart 318 power steering.It had a federal pump on it that was leaking really bad. I decided to switch from the federal style to the Saginaw style and use the March mounting kit. This turned out to be quite an ordeal. Because of this it created a hose nightmare. What I ended up doing was going to the pick a part junk yard and found a 86 Chrysler 5th Ave. The pump, mounting brackets,steering box are the same as the Darts. So figure I will take the pump hoses and for good measure the piece that the hose mounts to on the steering box. I get everything back to the house and start compairing all the parts. Everything is exactly the same except the hose mounting for the steering box. I thought no big deal. I will simply replace that house mounting valve assembly on the steering box and everything should be fine. When I replaced that valve assembly I was very careful not to move that spring Pin thing that is in the steering box that fits into the valve assembly. If you have taken one apart you know what I am talking about. I put everything back together and started the car. As soon as I did the steering wheel ripped out of my hands and went hard left very fast. I have taken the valve off the steering box several time and doubled checked everything and it all looks and measures the same including the slide valve.

What is causing the wheel to turm so fast and so hard?
 
In-line steering gear (as I remember - it has been a while) you can centre the valve assembly. Leave the two or three bolts that hold the valve housing snug, but not tight. Use a small dead-blow hammer to gently tap the valve housing forward or rearward until the steering stops self-turning in either direction. We used to do this on the hoist with the wheels off the ground because you need to ensure the valve is perfectly centred or else it will cause a pull in one direction or the other. Best as my memory serves me, this was the procedure. I'll double check on this tomorrow for you (if no one else steps up with a more certain answer...?).
 
Did a little checking... move the valve forward (downwards) to get the steering to go right - back (upwards) to go left. Be aware that we are talking about miniscule movement of that valve housing - 0.5mm to 1 mm (1/32" to 1/16") at a time. Best put the front wheels up with jack stands under the lower control arms for this.

Also, if the wheel is snapping hard over right now, the pump is likely going to max pressure - you might want to start by setting the housing to what you think is the centre of its movement on those attaching bolts before you start the engine again. Less wear and tear on the flow control valve, pump, hoses, gear and pressure relief valve that way!
 
You guys are GREAT I knew I could count on you guys to help me. If you could check for me tomorrow I would appericate it very much.

I am going to try and bump it around a little and see what happens I will let you know.

Thank you guys again.
 
Actually it didn't work. I am missing something. I don't know if it makes a difference but I made sure the wheels were straight took the valve off and made sure the "pin" with the spring was in the steering box all the way. Put the valve back on. Same thing. I moved it all the way forward. Same left turns. All the way back turns to the left.
 
Was the valve in the housing centred before you put the housing on? Can't remember if that is a split valve with the pin in the middle of two halves - check when you have it off. If you cannot find out, I will post more tomorrow evening.
 
Also- get someone to move the steering wheel slightly left and right while the housing is off and make sure the pin responds to wheel input. You should feel a slight movement of the pin any time there is torque on the steering wheel.
 
OK I will try that tomorrow. I will also take some pictures and post them
I appericate your input.
 
OK I think I have the valve in the center but now it feels as if I have no power steering at all. What the heck?
 
Sounds like that valve is sticking in the housing. The "pin" that comes up and engages the valve is moved by a thrust bearing trapped between two reaction springs. When you turn the wheel, the worm shaft (input shaft) develops end thrust against the ball-nut (think of holding a nut with a bolt threaded into it). this moves the thrust bearing (and the pin or lever) in the direction of the thrust. There is not a lot of force delivered by the lever, so the valve must be very free to move.

The valve is simple spool valve. In its centred position, it connects the right and left turn chambers to inlet and exhaust oil - keeping equal pressure on both chambers. As soon as you move it the slightest bit (a few thousandths of an inch) it partially blocks the return oil from one chamber and opens it to the supply from the pump. At the same time, it opens the other chamber more to exhaust (return oil), and cuts that chamber off from pump supply. Pressure builds on one side, the ball nut moves and removes the thrust from the pin, allowing it to re-centre. Valve goes back to idle (straight ahead)

If you take the plug off the end of the valve housing and carefully slide the valve out, you can clean it and check it for burrs or nicks. Some crocus cloth is good to polish it, like you would a valve in a transmission valve body. Check the housing for burrs too - cleanliness is critcal here - the clearances are 0.001" or less in some cases. No lint from cloths, steel-wool or any else that can jam the valve. Make sure the valve moves very freely before you put the housing back on.

sorry if the explanation is long... I believe the more you know about what is happening inside, the better you are able to figure out how to fix things.
Also - this is all from memory - I haven't been inside one of these in 25 years or more. If someone else is more up-to-date, please pitch in!
 
thats pretty much an out of textbook anwser, thats what my automotive service and repair book says from collage
 
LOL - must be an old text book then - these offset boxes are not what we teach about anymore. Somewhat easier to explain than the inline Saginaw boxes though.
Did cleaning the valve fix the problem?
 
Actually I have been messing with it for two days now. The valve slides back and forth freely. There is no binding throughout the full stroke of the valve. I put everything back together and messed with it over and over again and I think I have it close. Because what is happening now is I will start the car and the wheel will stay in the center, it won't move in either direction. However if I try to turn the wheel to the right it will kind of hesitate then turn to the left a little. Then if I do the same in the other direction it will turn a little to the right. Also if i "bump" the valve less then a 1/64" or less it will start to shimmy back and forth kind of hard but, stay in the center. In other words it won't go either left or right when it is shimming. I can bump that shimmy out but then it will go back to wanting to turn in either direction depending on which way I bump it.

I have the wheels of the ground while doing all this.

Thanks again for your help.
 
In the way of an update. after spending hours tapping the slide valve back and forth ever so slightly. I did the only other thing I could think of and that was to order a new gear box. I bought it from Steer and Gear in Ohio. Nice people. very helpful. As I explained my problem a nice but matter of fact and I heard it all before guy named Jim asked if it was a stock box. I said yes. He said "well son (im 48) said you could of messed with that valve for a week and would probably never got it right. Expalining that with the stock boxes being so sensitive to input made them next to impossible to get the slide valve in the exact spot. Even tightening the valve down will through them off.

So that is that. Until next time my friends. Thank you for your advise and help.
 
I worked at a garage and we did all the repairs for Hilsborough Co. Sherriff Dept. They were all Coronets. Like 64SignetConv explained is exactly the procedure we use when we had to reseal a P/S box. I don't know why you had so much trouble with yours, maybe the different years of the valve and your steering box? But i never had a problem centering the valve. We did it with the front wheels off the ground and we would rev the engine up before we let it down to make sure the wheels stayed center.
 
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