Three point hitch draft control M4700

[JWR]

DITTO what JWR stated!!
IMHO float position of 3pt hitch on most brands of tractors including Kubota & JD is any placement of 3 pt control lever besides fully raised. The farther forward of fully raised the control handle is placed the wider range of the 3 pt hitches ability to float.

Depth positioning(control) has been misunderstood by many tractor owners/operators for many yrs.

100% agree on float interpretation. That is universal. Back on Draft Control, yes, it is very often misunderstood even by dealers and some mechanics. I think that is partly because it is a small % of utilization these days. Very rarely do most users want or need anything other than position control. Some evidence of that is that Draft control is optional and/or just not there on many newer tractors. Back in the day the Fords and Fergusons all had it as part of the "Ferguson system" which really pioneered mass market 3pt hitch technology. In those days there was a lot more plowing going on.

 

[Complete Turf Care]

Based on his video, I think you'd have to say there is something wrong and his position control is failing to work... Hmmm. The fact that he can't turn his lowering rate knob may be a clue...

But? What is wrong? Why is the position control lever not doing anything?

 

[LouNY]

OK, here goes nothing;

Draft Control 101
Draft control refers to the concept of maintaining a consistent draft (pull) on a 3 point hitch.
What is draft, for this discussion draft is the amount of pulling force to be used for the operation performed
by the tractor being used.
This pulling force has to be monitored for draft control to work, most small and mid sized tractor will monitor
this force at the top link mounting point. Many top link mounts will have more then one set of holes where the
top link can be pined into. A tractor using draft control monitored this way, will in the manual describe which
position will provide the most sensitive position as well as the least sensitive. This is for both ways of monitoring
the draft pull of the top link,many tractors will utilize a mechanic method and linkage for the draft control, some
will utilize an electronic sensor. Many of the more modern (the last 30 years) large tractors will actually have the
draft control sensor on the lower three point main lift arms to directly monitor the pulling force.
The designed function of draft control was to maintain a constant and consistent pull on the tractor. By monitoring
the draft (pulling force) and adjusting the level of the three point implement, Raising the implement as it pulled harder
to reduce the pulling force required as the ground conditions changed and then lowering the implement as the pulling
forces decreases to increase the pulling force"draft"to the desired force. This operation would result in a more constant
tractor loading, NOT a more consistent plowing depth. The tillage depth would vary to maintain a constant tractor load.
The position control when used with draft control is designed to limit the lowest depth a tillage implement is to
be allowed to drop to or pull down to.

Setting the draft
A common method to set the draft and position control is, with the draft control disabled or set to it's least sensitive
setting while moving forward with the tillage implement in the ground and working, is to set the position control and let the
implement pull down to the maximum desired depth when that depth is achieved the operator should begin increasing the
sensitivity of the draft control until the implement is just beginning to lift but is still at a good working depth.
When this has been accomplished the draft control will be monitoring the force required to move the tillage implement
through the ground. As soil conditions change such as a heavier soil or more compacted ground the tillage implement
will lift higher to reduce the draft requirement to pull the implement. As the ground condition become more favorable
and the pulling force starts to decrease the draft control will begin lowering the implement to maintain the constant
pulling force. In the same vein if soil become such that the draft requirement becomes less then the original settings such
as a looser or sandy soil then the position control which has set the maximum depth takes over the control and maintains
the maximum depth of tillage as was set, as conditions change again and the draft required to pull the tillage implement
increases the draft control will reassert control to reduce the required draft to the initial setting.​

I hope this helps to explain draft control and it's setting. It is not used much any more as most tillage operations are traction
limited not power limited. Draft control will not help when the draft requirement doesn't change but the traction does, a lose of
traction does not necessarily factor into the draft requirement. As with a lose of traction the draft as sensed will be lessened
and draft control will allow the implement to go to it's lowest position control setpoint. By which time the operator has yanked
the position control to raise the implement to avoid becoming stuck and would then have to revert to the previous position setting.
This one reason many position control levers will have an adjustable stop which can be set for the lowest desired operation.

 

[Complete Turf Care]

That's a good explanation of draft. But that still doesn't answer the question of what's wrong with my tractor. Why does the position control lever not do anything? Why can I only lift the 3 point with the draft control lever? Is something broken, or is something not working properly?

 

[JWR]

That's a good explanation of draft. But that still doesn't answer the question of what's wrong with my tractor. Why does the position control lever not do anything? Why can I only lift the 3 point with the draft control lever? Is something broken, or is something not working properly?

Absolutely! That's the real question and we do not know. I suggested the "lowering speed knob" being stuck and not working is a strong clue to what is wrong and I still think so. Because the lift DOES move up and down in your video (never mind the control settings) that means your hydraulics are working, you have flow to the lift cylinder, etc. I suspect something in the control linkage is stuck which is why the "lowering speed knob" won't turn. I don't own a 5740 so can't go out and inspect one or study it. Your position control lever operates an hydraulic valve so it is possible the valve is bad but in many, many years I've never seen that go bad. Has it ever worked properly while you have had it ? I'm betting is has never worked right while you owned it. Was stuck when you bought it.

You might end up having to have a dealer look into it. I think you will find the fix is all labor. Doubt seriously there's a bad valve.

 

[JimB77]

LouNY
I disagree with this statement
[/quote]
Draft control will not help when the draft requirement doesn't change but the traction does, a lose of
traction does not necessarily factor into the draft requirement. As with a lose of traction the draft as sensed will be lessened
and draft control will allow the implement to go to it's lowest position control setpoint. By which time the operator has yanked
the position control to raise the implement to avoid becoming stuck and would then have to revert to the previous position setting.[/quote]

When plowing with a moldboard plow or tillage tool if ""traction is lost"" the pushing/pulling motion on centerlink attaching point on tractor will change due to relocation(movement) of center link attaching hole on the tractor due to less plow draft therefore draft mechanism should raise plow depth if tractor draft is functioning as designed.

Operator yanking 3 pt control lever indicates operator isn't familiar with correct draft control use or draft control doesn't operate as designed.

I think Complete T C needs to check to be sure "rate of drop valve" is opening sufficiently when control knob is turned CCW. In order for draft control to operate as designed the oil trapped by control valve in rockshaft lift circuit must exit circuit in a timely matter of time

I have more experience moldboard plowing with JD lower 3 pt link sensing & tractor operator can view moldboard plow rising/lowering as tractor is pulling plow turning the soil.

 

[LouNY]

That's a good explanation of draft. But that still doesn't answer the question of what's wrong with my tractor. Why does the position control lever not do anything? Why can I only lift the 3 point with the draft control lever? Is something broken, or is something not working properly?

It is hard to say exactly what is wrong with your lift arm control without being there. Looking at your picture in post #1 and trying to comprehend what the manual is describing. I would say that to reduce the sensitivity your draft control lever should be forward to the stop in your picture, apparently that would be the least sensitive draft position. Then per the manual the position control lever should raise and lower your implement.
Which top link bracket pin holes are you using. The upper most location may be the least draft sensitive.
If with the draft control at the forward stop if the position control does not lift the implement then the function of the draft control lever needs to be checked out. Is it operating a cable or a linkage going to the internals of the tractor. It will take a service manual to get that adjusted correctly.
It could be the rate of change adjustment but it is allowing motion to occur.
With this being a "97" model and 24 years old the draft control and position control linkage could be all screwed up and the sensing portion of the draft control damaged or misadjusted.
Good Luck with her.

 

[LouNY]

LouNY
I disagree with this statement

Draft control will not help when the draft requirement doesn't change but the traction does, a lose of
traction does not necessarily factor into the draft requirement. As with a lose of traction the draft as sensed will be lessened
and draft control will allow the implement to go to it's lowest position control setpoint. By which time the operator has yanked
the position control to raise the implement to avoid becoming stuck and would then have to revert to the previous position setting.[/quote]

When plowing with a moldboard plow or tillage tool if ""traction is lost"" the pushing/pulling motion on centerlink attaching point on tractor will change due to relocation(movement) of center link attaching hole on the tractor due to less plow draft therefore draft mechanism should raise plow depth if tractor draft is functioning as designed.

Operator yanking 3 pt control lever indicates operator isn't familiar with correct draft control use or draft control doesn't operate as designed.

I think Complete T C needs to check to be sure "rate of drop valve" is opening sufficiently when control knob is turned CCW. In order for draft control to operate as designed the oil trapped by control valve in rockshaft lift circuit must exit circuit in a timely matter of time

I have more experience moldboard plowing with JD lower 3 pt link sensing & tractor operator can view moldboard plow rising/lowering as tractor is pulling plow turning the soil.
[/QUOTE]

Your last sentence explains why you would believe that the draft control responds to lose of traction.
It does with lower link sensing.

With top link sensing a lose of traction is often considered low draft required which will attempt to lower the tillage implement.
The reverse of the required corrective action.

 

[RickB]

Loss of traction will by definition DECREASE the draft signal and cause the 3pt linkage to lower if draft control is in use.

 

[ptsg]

That's a good explanation of draft. But that still doesn't answer the question of what's wrong with my tractor. Why does the position control lever not do anything? Why can I only lift the 3 point with the draft control lever? Is something broken, or is something not working properly?

Have you checked the linkage from the top link bracket to somewhere in the rockshaft housing? It almost looks like something is wrong or disconnected there and it's constantly sending feedback to the 3 pt control valve to lift the 3 pt.