International 300 steering geometry problems...

[LD1]

Well, I have been trying for the last day and a half to get this steering dial in an maybe I am just over thinking it or overlooking something simple....hopefully, someone can help out that is familiar with the manual steering on these tractors.

Those that are familiar, there is a mechanical stop on the spindle "knuckle" itself that limits how far the spindle can rotate. It allows a certain amount of travel and no more.

The pitman arms on the steering gearbox can only move so far also.

Well...these numbers are exactally the same when measured. No issues if the front axle is level. But when the front axle tries to pivot:
On the side coming up, the distance is getting shorter between the spindle knuckle and the gearbox pitman arm.
On the side going down, the distance is getting longer.

The issue is the knuckes on the spindle are against the stop. This causes a bind. Not sure how I can adjust anything to make the issue go away. Cause the gearbox and spindle travel is the same. But nothing to account for the front axle pivoting and changing things.

So just wondering if this is the way it is supposed to be?? And when the axle pivots, it just feeds back through the steerng colum??

I have also had the steering gearbox appart. Which leads me to my next question...

The left hand shaft, that has the nub driven off the worm gear, has 3 teeth. The right side has 4 teeth. So common logic, I put the center tooth of the 3 gears in the middle of the 4 teeth of the right. But that puts the alignment mark way off on the pitman arm. Thats not a huge issue as I can jump a few splines to compensate, but the way I took it appart, the gears werent centered. The middle tooth of the 3 gears was between the first and second gear on the 4-tooth shaft. Just didnt seem right. And would also cause a lot of slop when the right side pitman arm was at its furthest forward position.

I dont think thats the issue though. cause I can (and did) re-position the pitman arm to compensate. Hopefully someone has some knowledge of these gearboxes. Not sure what else to do.

And if anyone has a 300u with manual steering, One thing I would like to see is a shot of the left and right side pitman arms, with the wheels pointed straight ahead.:thumbsup:

 

[LD1]

No one has any ideas??

I subscribed to Red Power Magazine forum, but waiting on an administrator to approve me so I can post:mur:

 

[300UGUY]

I don't have any pics of the steering on my 300U. I am thinking that you have the arms reversed or something, for them to be binding.

 

[300UGUY]

Does your manual show the steering, like where to lube it?

 

[xtn]

I have no idea about the geometry or inner workings, but I've got an idea about something....

You say that when the axle pivots, one side shortens up and the other side lengthens. You say that since the pitman arm is against the stop, this sorta creates a bind condition. Reading between the lines I'm assuming that since the pitman arm is against a stop you must have the steering turned full to one side or the other, right? But still, I don't see how that creates a bind unless the turning angle of the wheels themselves is prevented from moving. In other words, as the axle pivots and one side shortens while the other side lengthens, the length changes should result in slightly changes steering angles at the wheels, right?

So if I understand correctly, you've just got what is commonly referred to as "bump steer." That's when change of height of the wheel relative to the chassis results in some steering change due to the geometry. It's very difficult to completely eliminate bump steer in a suspension design. Good race car designers attempt to create geometry that takes advantage of what cannot be eliminated; they try to get a good predictable, linear curve of bump steer such that the outside wheel in a turn is progressively steered straighter as the wheel is compressed up into the fender. This is conducive to smooth control if dialed in well. But honestly it isn't much worth considering with the usage profile of a tractor.

If I've misunderstood I apologize.

xtn

 

[LD1]

I don't have any pics of the steering on my 300U. I am thinking that you have the arms reversed or something, for them to be binding.

Does your manual show the steering, like where to lube it?

MAnual does show all the setups and how to align all the marks to put steering at center, and then adjust toe accordingly. Things arent binding because of lack of lube, they are binding because its against the stops.

 

[LD1]

XTN, bump steer is a good analogy.

Picture this....Front axle pivots. Lets say the right tire drops in a hole and the left comes up, The right tire going down is getting "farther" away from the steering gearbox. Well since the tierod is a fixed lenght, it "pulls" or causes the wheel/spindle to turn in toward the tractor.

The side coming up, the distance gets shorter, causing the tierod to "push" the wheel outward.

So in this case, with right tire (as viewed from the seat) drops into a hole, it will cause a bump steer to the left. No problem.

BUT, lets say the wheel is turned all of the way to the left already. Both spindles are against a mechanical stop. So as the right tire tries drops into a hole, the distance is lengthend, and the tierod tries to pull back on the spindle arm, but cant cause its against the stop.

Same thing on the left side trying to raise up, but cannot because it causes the tierod to try to push against the stop. Therefore, the only way the axle can have full pivot range, is for the steering wheel to be about 1/2 turn away from the end of its range...

OR, in other words, if the steering is turned hard left, and you hit some uneven ground, either something is going to break/bend, or the steeringwheel will be jerked 1/2 turn out of your hands....

 

[LD1]

pics may help.

This is the left spindle as viewed from the tractor:

Here, the wheel is turned hard left and the axle is level. You can see I am against the stop. So....the axle cannot raise up on this side if it needs to, unless the tierod pushes back against the steering box.



Here the wheel is turned hard right. Again, axle level and against the stop. So The axle can cannot drop into a hole if needed without trying to pull on the steering box.



Same deal on the other side. In that first pic, the axle cannot raise if needed, but is free to drop all it wants, but the right wheel would prevent that. In the second pic, the axle is free to raise if needed, but again, the right side is into the other stop.

So...when turned hard one way or another, one side is preventing the axle from pivoting one way, the other side prevents pivoting the opposite direction.

Its like the gearbox has too much travel. I dont think it should be able to go from stop to stop when level. Otherwise it has no room to compensate when pivoting.

And with the adjustable axle, the farther out the axles are extended, the worse it is.

 

[LD1]

I may have stumbled on a possible cause, but info is sketchy at best.

I found an old thread on Ytmag that mentioned something about the 300u getting longer pitman arms somewhere around serial # 26000, as well as longer front spindle arms.

I am wondering if I possible have the longer pitman arms, and shorter front spindle arms causing the issue??

Anyone with a 350U or similar model be able to measure the lengths of their pitman and spindle arms??

 

[LD1]

here is what I was refering to
I.H. 300 utility steering box problem - Yesterday's Tractor Co. (#693373)