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