L4740 draft control not working

[JeffInCO]

I used the 3-point on my L4740 for the first time this weekend, with a 72" box blade. When I bought the tractor, I had the dealer install the draft control option... so today was the first time that I've tested it.

Unfortunately, it seems that the draft control is not working at all. Position control works fine, with one minor issue.

Since I suspected that draft control wasn't working, I tried raising the box blade just to the point that was off the ground. I then used a crowbar to rotate the box blade forward a very small amount, which puts pressure on the top link. I expected to see the 3-point lift the implement up a small amount, but nothing happened at all. I could even see the draft control linkage move ever so slightly.

As for position control, there's also a minor issue. If I move the position control lever to the fully-raised position, the 3-point lifts the implement to the maximum height off the ground (as expected), but it seems that it continues to try to lift the implement even higher, which it cannot. I can hear the hydraulic pressure relief valve open, and the tractor just sounds very unhappy.

Every now and then, this doesn't occur. Instead, the implement goes to the top, then the 3-point clicks and shuts off it's attempt to further raise the implement. I suspect this is how it's supposed to work.

So, now, my questions:

1) Does anyone have the installation instructions or shop manual for the draft control? Is there any published test that I could perform? Any suggestions as to what I might check?

2) Should the position control behave as I described above? If not, what might be wrong?

Thanks,

Jeff

 

[KennyV]

used a crowbar to rotate the box blade forward a very small amount, which puts pressure on the top link.


If I move the position control lever to the fully-raised position, the 3-point ...continues to try to lift the implement even higher,...and the tractor just sounds very unhappy.


1) Any suggestions as to what I might check?

2) what might be wrong?



Jeff

Jeff... I think the two problems may be related. AND the fix for both should be a slight adjustment for the position control, to allow it to cancel the lift a little quicker...

on the other hand I have never been able to get a draft control to trip using a crow bar... a very long pry bar maybe... KennyV

 

[_RaT_]

The position control should not do that, it needs adjustment. There is typically a adjustment in the linkage from the position control lever back to the arm that operates the hydraulic control valve in the tractor. I have had to adjust that linkage on my Kubota L4850. The draft control also has adjustment and is quite sensitive to adjustment.

If you do not adjust the position control and try using the tractor with the rear position control lever in the all the way up position it is similar to what happens if you try to leave the loader, TnT etc hydraulics valve in the flow position. I suspect the oil will get extra hot as a result. You will want to adjust it. In the mean time, don't put the control in the very highest or up position.

I used the 3-point on my L4740 for the first time this weekend, with a 72" box blade. When I bought the tractor, I had the dealer install the draft control option... so today was the first time that I've tested it.

Unfortunately, it seems that the draft control is not working at all. Position control works fine, with one minor issue.

Since I suspected that draft control wasn't working, I tried raising the box blade just to the point that was off the ground. I then used a crowbar to rotate the box blade forward a very small amount, which puts pressure on the top link. I expected to see the 3-point lift the implement up a small amount, but nothing happened at all. I could even see the draft control linkage move ever so slightly.

As for position control, there's also a minor issue. If I move the position control lever to the fully-raised position, the 3-point lifts the implement to the maximum height off the ground (as expected), but it seems that it continues to try to lift the implement even higher, which it cannot. I can hear the hydraulic pressure relief valve open, and the tractor just sounds very unhappy.

Every now and then, this doesn't occur. Instead, the implement goes to the top, then the 3-point clicks and shuts off it's attempt to further raise the implement. I suspect this is how it's supposed to work.

So, now, my questions:

1) Does anyone have the installation instructions or shop manual for the draft control? Is there any published test that I could perform? Any suggestions as to what I might check?

2) Should the position control behave as I described above? If not, what might be wrong?

Thanks,

Jeff

 

[pndqkb]

Jeff,
I also have a L4740 and had the same problem of trying to continue to lift.
The ajustment is on the left (viewed from rear) lift arm.The rod with the two jam nuts needs to be ajusted a little longer.Lengthen a little until it stop trying to lift.
I also have a draft control but have not tried it yet.
Dane

 

[JeffInCO]

Thanks for the replies...

As soon as I noticed the position control problem, I stopped lifting the implement all the way so as to avoid overheating the oil or damaging something else.

I was using a four-foot pry bar to rotate the back blade. I definitely rotated it enough to see the draft control linkage move. Maybe just moving isn't adequate, though.

I'll try adjusting the position control linkage. It makes sense that this would fix the position control issue, although I doubt that the draft control issue would be affected by this as I did not have the position control in the fully-raised position when I did the pry-bar experiment.

Jeff

 

[beppington]

Jeff,
I also have a L4740 and had the same problem of trying to continue to lift.
The ajustment is on the left (viewed from rear) lift arm.The rod with the two jam nuts needs to be ajusted a little longer.Lengthen a little until it stop trying to lift.
I also have a draft control but have not tried it yet.
Dane

Not that I have had any 3ph problems (yet!?!), but when discussing my tractor in general this is exactly what my dealer explained to me can happen sometimes.

 

[Larry Caldwell]

Why don't you test the draft control under load? Set the teeth low on the box blade, set the position control low enough to really make the tractor work, and see if the draft control lifts the box when the tractor really starts to grunt.

 

[JeffInCO]

The draft control does not work under load.

I set the draft control to maximum; I tried both with the position control at the lowest position and with the position control just at the point where the blade is hitting now and then (only at the high spots). In neither case was I able to get the 3-point to lift the implement in response to load on the blade. The tractor was definitely doing a bit of "grunting" with the position control at the lowest setting.

(I also tried other settings on the draft control... right in the middle, minimum, just to make sure I'm not confused about which extreme is which.)

I was hoping to use the draft control feature with the box blade to help level my drive. It has quite a few ruts/bumps/dips after a year of construction traffic.

Thanks,

Jeff

 

[pndqkb]

Jeff,
You also have, on the tractor, four different positions to attach the top link.
The top holes would be the most sensitive. I would think you would want to
be in the top hole since a box blade doesn't dig as deep as say a plow or a
disk.Did you get your over lift problem squared away?You may need to do a
little adjusting on your draft control linkage.Let us what happens.
Dane

 

[JeffInCO]

I haven't adjusted the position control linkage yet (no seat time since Sunday). I will definitely do this before I use the tractor again... I suspect that this will fix the position control issue.

Changing the topic a bit... what is the best repair manual for the GrandL's? Are there any good aftermarket manuals out there? Last time I went to the dealer I asked about the L4740 manuals and was told that I would have to buy a small fortune's worth of manuals that cover multiple tractors in order to get a complete set for mine.

Thanks,

Jeff

 

[_RaT_]

I don't find draft control to be that helpful. I prefer to find the right top link adjustment (via my hydraulic top link) as well as making several passes doing a leveling run to get rid of the really bad spots first. I often do not lower the box blade all the way down but rather lower it until I just touch and then stop the positioning lever there. Sometimes you simply do not want the box to follow the terrain. It takes practice. I find the draft control simply cannot react the way I need it to. It works well when moving large amounts of material or when I have the rippers down to help keep me from spinning the tires.

The draft control does not work under load.

I set the draft control to maximum; I tried both with the position control at the lowest position and with the position control just at the point where the blade is hitting now and then (only at the high spots). In neither case was I able to get the 3-point to lift the implement in response to load on the blade. The tractor was definitely doing a bit of "grunting" with the position control at the lowest setting.

(I also tried other settings on the draft control... right in the middle, minimum, just to make sure I'm not confused about which extreme is which.)

I was hoping to use the draft control feature with the box blade to help level my drive. It has quite a few ruts/bumps/dips after a year of construction traffic.

Thanks,

Jeff

 

[rjkobbeman]

If your draft and position controls are anything like mine (I have an M8540), there are "float" positions for each of the controls.

According to my manual, unless you are using a combination of both draft and position control, you should have one or the other in the float position.

For example, if you are using draft control only, the position control lever should be in the float postion. If you are using position control only (which is what I always use), the draft control lever should be in the float position.

On my tractor, the float postion is all the way forward. This happens to be the total down postion.

If neither lever is in the float position, this is the "mixed control" that the specs and manaul refer to. Mixed control is basically draft control, however the position control will not allow the implement to go lower than the position control allows... no matter what the draft control is set to. Anything above the position control setting, the draft control will kick in an control the position. Obviously, if the position control is set too high, the draft control will have no affect.

From my understanding of draft control, you really have to have a plow dig in hard to start seeing the draft control in action. Your not going to see it by hanging a cutter on the end. A box blade may not have enough force to push the top link against the tractor enough to cause the draft control to sense anything. If you have more than one top link attachment point on the tractor, you should use the lowest hole in order to have the most leverage against the draft control. This may or may not help.

 

[_RaT_]

I consider the position control to always be in float since it cannot apply any down pressure short of the weight of the implement. The difference of course with the 3 pt set up over the loader being used in float is that you can put a lower limit on the 3 point by not putting the position control lever all the way down. That is something I do quite frequently when grading.

If your draft and position controls are anything like mine (I have an M8540), there are "float" positions for each of the controls.

According to my manual, unless you are using a combination of both draft and position control, you should have one or the other in the float position.

For example, if you are using draft control only, the position control lever should be in the float postion. If you are using position control only (which is what I always use), the draft control lever should be in the float position.

On my tractor, the float postion is all the way forward. This happens to be the total down postion.

If neither lever is in the float position, this is the "mixed control" that the specs and manaul refer to. Mixed control is basically draft control, however the position control will not allow the implement to go lower than the position control allows... no matter what the draft control is set to. Anything above the position control setting, the draft control will kick in an control the position. Obviously, if the position control is set too high, the draft control will have no affect.

From my understanding of draft control, you really have to have a plow dig in hard to start seeing the draft control in action. Your not going to see it by hanging a cutter on the end. A box blade may not have enough force to push the top link against the tractor enough to cause the draft control to sense anything. If you have more than one top link attachment point on the tractor, you should use the lowest hole in order to have the most leverage against the draft control. This may or may not help.

 

[rjkobbeman]

I consider the position control to always be in float since it cannot apply any down pressure short of the weight of the implement. The difference of course with the 3 pt set up over the loader being used in float is that you can put a lower limit on the 3 point by not putting the position control lever all the way down. That is something I do quite frequently when grading.

Yeah, but if you are trying to use the draft control and your position control is not all the way "down", your 3ph will not drop below the level that the position control is set. This may or may not be what you want to happen.

If your position control is set in the float postion (all the way down), your 3ph can "float" up and down... from top to bottom. The draft control would then be use the control the depth -- which in the case of top link sensing, would be how much force the top link is being pushed into the tractor.

 

[_RaT_]

Probably more a matter of semantics. What your saying is correct. The position control is just that, a way to adjust how far down (or up) the upper links let the implement drop (or raise). All the way down is the bottom extent to which the links can go. My comment is that you don't have all the way to the bottom and then float, you just have all the way to the bottom. Draft control simply operates off the load being applied to the implement and lifts and drops as that load increases or decreases, basically a semi automatic position control. Using it as a means for leveling things out has never been what I would consider its strong point. Keeping the wheels from spinning or the engine from stalling are.

Yeah, but if you are trying to use the draft control and your position control is not all the way "down", your 3ph will not drop below the level that the position control is set. This may or may not be what you want to happen.

If your position control is set in the float postion (all the way down), your 3ph can "float" up and down... from top to bottom. The draft control would then be use the control the depth -- which in the case of top link sensing, would be how much force the top link is being pushed into the tractor.

 

[Larry Caldwell]

Changing the topic a bit... what is the best repair manual for the GrandL's? Are there any good aftermarket manuals out there? Last time I went to the dealer I asked about the L4740 manuals and was told that I would have to buy a small fortune's worth of manuals that cover multiple tractors in order to get a complete set for mine.

Thanks,

Jeff

That's nonsense. The shop manual for your tractor will cover all the available configurations (GST, HST, etc.), but it will be specific to the L4740. You should also buy a parts manual for your tractor. Not only can you always order the right part by number, but it has all those nifty exploded drawings that show how things are supposed to go back together.

Both manuals together should cost you about $250. If they help you avoid one service call, they have paid for themselves. Kubota manuals are pretty well done.

You just got somebody at the dealer who didn't know what they were talking about. Try again. Buying a tractor without manuals is like buying a tractor without tires.

 

[rjkobbeman]

Probably more a matter of semantics. What your saying is correct. The position control is just that, a way to adjust how far down (or up) the upper links let the implement drop (or raise). All the way down is the bottom extent to which the links can go. My comment is that you don't have all the way to the bottom and then float, you just have all the way to the bottom. Draft control simply operates off the load being applied to the implement and lifts and drops as that load increases or decreases, basically a semi automatic position control. Using it as a means for leveling things out has never been what I would consider its strong point. Keeping the wheels from spinning or the engine from stalling are.

I think I may have just read your post too fast -- I have a bad habit of doing that.

 

[KennyV]

I have used draft control on larger tractors when plowing... I can't imagine being able to set it sensitive enough to make it respond quick enough to give any positive results with a box blade...

I know I have read about folks trying to do it ... I've never seen a set up that it could ever work with...
For maintaining a long drive or a road there is nothing as easy and quick as a wheel mounted grader blade...
If you do ever get the draft to work quick enough to do this do post back about it. KennyV

 

[_RaT_]

Your comments reflect mine. Response is far to slow to be able to use it as a grading tool with a box blade, but then, I don't think that is really the purpose of the draft control. It would seem more useful for ground penetrating type attachments.

I have used draft control on larger tractors when plowing... I can't imagine being able to set it sensitive enough to make it respond quick enough to give any positive results with a box blade...

I know I have read about folks trying to do it ... I've never seen a set up that it could ever work with...
For maintaining a long drive or a road there is nothing as easy and quick as a wheel mounted grader blade...
If you do ever get the draft to work quick enough to do this do post back about it. KennyV

 

[JeffInCO]

I've read a handful of other threads here on TBN about using draft control with a box blade for grading.

Maybe the effectiveness of the draft control for grading depends on the tractor...

I would try it out also on my Ferguson TO-30 (one of the first tractors with draft control), but my TO-30's 3-point needs a part that I cannot purchase new... need to find a parted-out Ford 8N or Ferguson TO-30 to fix it.

Jeff