Hi,

I am trying to use a power steering control valve for a tractor steering application. I thought the ball stud for the pitman arm would move in the direction of the green arrow as the pitman arm and relay rod move in that direction. Instead I found that the ball stud rotates in the direction of the red arrow. Can someone shed some light as to how this control valve works in the steering system?

Thanks

 

How about just get the correct power steering control valve.

 

Once that tapper is tight in the relay rod. It actually does push and pull in the direction of the green arrow. Which of course switches fluid flow from one direction to the other.
At straight ahead no fluid flows. Pushing to the right or left fluid flows but of course in opposite directions.

 

Thanks for the reply 4-vettes. I thought that it had to go in the direction of the green arrow, and I tried pushing the stud in that direction but it wouldn't budge. And based on the clearances, it doesn't look it could move much. So there must be a high stiffness spring on the control side, and it takes very little movement to change flow direction.

 

If a guy follows the hydraulic path, the stud is the valve, (or 'switch' if you will) which directs hydraulic oil flow one way or the other. For assistance this way or that.

Interestingly ...The Common Saginaw-style 'modern' power steering boxes have a valve too. It's integral to the power steering box ..like a Borgeson. The main input shaft that sticks out is a 'stub-shaft' separate, and moves independently, from the lower 'input' shaft. That small amount of 'play' on the input shaft is what ports fluid one way or the other. Works great for highway sedan cruizers, but that "Play" is I believe why Zora never went with a regular power steering box, like a Borgeson (for example) on a C2/3 ...when he easily could have (at less expense). At the limit during a performance run ...a properly set up manual box would be 'tighter'. On a P/S box there's always going to be a minute amt of 'slop' (shall we say) which is the movement the valve (input stub shaft) needs to do it's job. Which is also why they say you can't adjust the top screw on a power steering box (by 'feel') as effectively as you can a manual steering box.

But the separate stud/control valve is simple in concept. They work. Probably tens of millions of cars used them back in the day incl early Mustangs. Yeah, can even adapt to a tractor. Hopefully your wheels aren't very big and duty not very severe. Then the integrated Saginaw-style system took over. Then Rack & Pinion came along. Simplified everything and even tighter yet. Now we have EPS, electric power steering 'innovation' which adds a lot more components, sensors, motor, belt, electronic board (which can get wet and fail)... lot of complexity (and possible failure points) to a R&P system. But no hydraulics.

Ok ...that was my man-splain of the day, sorry ...

Hope your tractor install works out!

.

 

It's a ball...it 'rocks'. The movement is transferred internally to regulate flow to the actuator ram.

 

This same system was used on fork lifts and other equipment. Difference being the valve was connected directly to the cylinder. So that may be the better way to go for a tractor.