q on hydrostatic steering

sotxbill

Well-known Member
On the fully hydrostatic steering, when plowing, at you work you way down the row, the steering wheel will eventually works it way to the left, more and more... Especially if you have a spinner on the steering wheel, it will start say at the 9 oclock position and end up at 3 oclock by the time you at the end and turning around... I have seen it especially on the 7710 series but the 6700 does it as well... Is there an explanation for this... maybe the way the power is fed into the steering motor or the wheels or toein pulls a bit one way over the other, tire wear on the front end???? I know when you kill the engine if your holding the steering wheel you can feel it kick/ease a tiny bit one way.


A customer was asking me to explain it, and all I can say, is that they all do it. Got to be a better explanation....

Apparently my photos are from down under.

Thanks in advance.
mvphoto17688.jpg
 
just about all our stuff at work with orbital steering does that. if you spin them off, they should still pump and move the tires albiet slowly.
 

yes, but he was wanting some kind of expaination. I have rebuilt the early ford motors with the torque sensors in them and could explain them, but not the newer systems.

As Ricci Recardo said, "LUCY!, You got sum 'plaining to do!"
 
I would say if the wheel creeps then you either have a leak in the steering cylinder or in the steering motor. Mine do not creep... The only ones I had that did creep were leaking at the cylinder.

Rod
 

This one has a brand spanking new steering cyl on it... It doesnt creep quickly or badly,, just after making corrections while driving down the field.. as you get to the end, you will find the "spinner" is not in the same position it started in. It seems to slowly end up more to the left... again,, its after driving a long ways and your making constant steering corrections to keep the pull/plow straight. After several rows the spinner will be half a turn off of where it started, Seems all of the hydrostatic units do this to some extent. A person was asking why... when on that 2002 model tractor, with a new steering cyl on it did the same as my tractors with older, much older cyls and hours on them.


Again,, maybe torque, hydraulic pressure, steering alignment? constant pull of the plow? The old proprietary units that ford build had a torque sensor built into them that would eventually twist to the right due to all the right hand turns in the field and it would distort the fine steering... I've never had the new motors apart to see the guts in them to figure out what would cause the very minute drift over time.
 
Howdy sotxbill,

You need a little B~S to brighten your day!!

When you are plowing, you have both right wheels in the furrow, and the prominent steering correction is to the left, to keep the front wheel up against (or near) the vertical section of the furrow, so the inside plow cuts maximum width. If you are conscientious, you are riding the steering all day long.

And you don't need a spinner anyway, so take it off and you won't notice these things!!
 

No, it happens when haying, cutting, raking, ripping, and just driving down the road.. Not enough for me to take exception, but a customer was complaining about it and wanted to know what causes it. I said,,, I dont know, maybe someone on the forum will know. Unlike the "fixed arm" tractors with power steering, where the spinner set at 9 oclock will ALWAYS be a 9 oclock, on a hydrostatic, it will be where ever it decides to be. He did not like that answer. I dont know what else to tell him. I guess he wants the little new holland emblem in the center of the wheel to always be facing up. You can't make this stuff up.

I do know that when I am haying and always looking over my right shoulder, its nice for the spinner to stay at 6 oclock as you feed the round baler and form your bale correctly. And if you wait long enough, it will eventually get there.... LOL.
 
It's the imperfections of hydrostatic steering. There will always be some (even if it's microscopic) leakage in the steering cylinder.

When you are mowing or raking you are predominantly turning in one direction. So the leakage is predominantly in one direction.

When you are on the road, the crown of the highway is causing you to hold a minor left hand bias on the steering to keep it the lane.

Don't let it bother you, it's just the nature of the beast.

Another example: Have you ever seen a 3 point lift that could hold a heavy load up for a day? Not likely. If so, how about a week? They all leak, it's just a matter of degree.
 
I dunno... Like I said, I've never had any of them drift like that if they weren't leaking, either in the cylinder or the torque generator. That said I may not notice very fine adjustments because I don't use wheel spinners. Never used anything but the palm of my hand.

Rod
 
What you describe is very much normal. As you said, it's more noticeable when a spinner is used, but only because the position of the spinner when pointed straight ahead makes for an obvious reference point that continually changes as the day goes on. I dare say that Rod's machines creep more than he realizes.

The cause is simple: internal leakage in the steering motor. Next time you're on the tractor, start the engine and turn the wheels full lock in one direction, then hold it there with moderate pressure. You'll notice the steering wheel continue to creep very slowly. Again, this is perfectly normal due to tolerances in the steering motor itself. The speed or severity of the creep will be directly proportional to the internal wear, meaning you won't see it as noticeable on newer machines.
 
Besides what everyone else has said, when the front wheels encounter resistance to turning and you turn the steering wheel farther to compensate, the pressure might be getting higher in the cylinder but the cylinder rod might not necessarily move as far for the same amount of steering wheel movement as when there's less resistance, even if there is no leakage. The excess energy in the way of higher pressure is converted to heat, so there's no breaking of the conservation of energy laws by not getting as much cylinder movement for the same amount of steering wheel movement.

I can't explain why it always seem to be in one direction to some folks, unless you're like a Nascar driver and only ever making left hand turns, or at least making more left hand than right hand turns or vice-versa, which would make sense in some situations like mowing or other duties.
 
Agreed.

All or my hydrostatic PS tractors do the same, whether new or not new.

All of mine have wheel spinners, and the spinners make the anomaly very noticeable but it remains noticeable, spinner or not, simply by observing the emblem in the wheel cap.

There is nothing wrong and the anomaly cannot be eliminated.

Dean
 

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