Question for L2900, L3000 and L3010 Owners: 3 point hitch

[jeconn]

Harvest, I checked my FIL's tractor again yesterday and the results were not as I posted previously. The lowering valve adjustment made no difference in raising. The 3ph did not raise as smoothly as I first thought. When i first checked it it was about 10 degrees outside, when i checked it yesterday it was about 60 degrees outside. Don't know if that made a difference. It raised in what seemed like 1/4" increments. Better than my 3400 but not like the JD in the video. I could live with it but it was not up to par with the other brands. His serial number is 56668. Let me know if you need any more info on this L3000 while I'm still here and I'll try to get you more accurate info this time. I still wonder if draft control is our solution. Does anyone know what is involved in installing this?

 

[Harvest Moon]

jeconn, thanks for the update.

If the parts book I have is reasonably up to date, then your FIL's L3000 has the original "Jerky" valve that has caused so much trouble in the L3400/L2800. And it sounds like, although not butter smooth it much better than your L3400.

I'm not surprised adjusting the lowering valve made no difference.

As previously stated, I'm not an engineer, nor a mechanic but from what I've gathered, the lowering valve is not much more than an adjustable check valve.

When the position control lever is raised, the hydraulic fluid rushes through the lowering valve and into the 3 point cylinder. If the lowering valve is closed the check feature blocks the flow and the hitch will not lower when the lever is moved down but will still allow the hitch to be raised further if it's not yet at it highest point.

Adjusting the lowering valve does not affect it check function as to allowing fluid to enter the cylinder but it does affect how fast fluid can leave.

Still noting that I could be wrong about this, the key difference between the lowering speed valve in the L3000 and the L3400 is a spring. I believe that this spring tempers the burst of fluid from the lesser quality position control valves to allow smoother 1/4 inch performance in the L3000. With the better quality position control valves, I believe it allows feather smooth performance.

In summery, what we've seen is an L3000 with 1/4 acceptable performance from the "jerky" valve and an advance lowering speed valve. We've seen lots of L3400/L2800's with the Grand L valve produce similar 1/4 inch performance with a basic lowering speed valve... and two reports of Grand L3010's with both the Grand L valve and advanced lowing speed valve produce smooth results.

Both models lowering speed valves use the same "valve body" and I strongly suspect they are interchangeable. I'm at a point where I'm convinced, unless someone more knowledgeable can contradict my hypothesis, that replacing the lowing speed valve (if possible) will result in the same level of performance improvement as replacing the position control valve. Replacing both valves will result in "Grand" performance.

If compatible, the lowing speed valve is a $90 part and would be easier to change than a tire. Two exposed bolts, pull, replace and re-bolt. Thats it. I think.

And if my conspiracy theory is correct, Kubota DOES NOT want you to know this.

 

[Harvest Moon]

More support for my new "spring" theory...

I just painstakingly compared 20 part numbers from:

the original L3400/L2800 position control valve... 31391-39002 and
the update version from the Grand L series........ 31351-39604 and

discovered that of the 20 parts I compared directly, 18 of them had IDENTICAL part numbers.

The original valve has 27 parts, the upgraded has 33. Some parts don't match but look the same. 6 are unique to the upgraded valve... they include a much larger spring called "spring spool" and a new "holder spring" and the various components to secure these springs within the valve.

The difference between the good position control valve and the bad is primarily in two springs. Just like the difference between the two lowering valves is a spring. I think the difference between the grand L's smooth hitch and the L3400's jerky hitch comes down to three springs. Those that have replaced their jerky valves to get 1/4 inch performance are only one spring away from a smooth hitch.

 

[daBear]

Well Harvest you have just about talked to yourself until a possible solution has been reached. Congratulations. Now, I have the better 3 point valve on my L2800 so what lowering vale spring do I need to order to try this out? I have a parts manual and all shop manuals for my tractor.

 

[canoetrpr]

Wow. I hope your theory is correct Harvest. There are many here, including myself, who would 'spring' for the advanced lowering speed valve with the extra spring.

I imagine that the HST fluid will have to be drained to change this valve - correct?

 

[Harvest Moon]

Me too canoetrpr. This valve is pretty high up, I was thinking I'd try to change it with the hitch in its full up position (cylinder full) but supported, then lower it manually after installation to force any air out before any live test. I think it's above the sight glass so I'm not too worried about loosing fluid.

daBear, thanks for your confidence.

Unfortunately, while triple checking my numbers I found a glitch in my theory. The L3000 input does not confirm my theory as I thought because the L3000 doesn't appear to have the improved lowering speed valve. I'm not sure how I made this critical mistake but it does leave some unanswered questions, like why is jeconn's FIL's L3000DT giving OK hitch performance with the lousy position control valve and a a springless lowering speed valve?

One answer may be that it's not, I may have read what I wanted to read in jeconn's post and he may have experienced what he wanted to experience as he reported the valve operated differently the second time he tried it.

And it's possible I did see a parts book with the improved lowering valve in this model but I can't find it now. I've probably put 20 hours into reviewing old threads, manuals and parts books to get to this point.

All that said, I still believe and support my theory though, as my triple check has confirmed the same advanced lowering speed valve is in the L2900, L3010 and the L3300. I believe in this theory enough to put my money where my mouth is but I'm not in a hurry and wanted to see if anyone could shoot holes in it first.

daBear, If you're wild enough to give it a try, in spite of my L3000 error, more power too you and best of luck... and if it works, or not, PLEASE let us know! But please don't hold it against me if you fail, I am only trying to help myself and share what I've learned in the hopes of helping others. The last thing I want is to waist anyones else's time or money.

The part from the L2900, L3010, and L3300 is TA040-34500 ASSY VALVE. The part it's replacing is 31351-37200 ASSY COVER CYL.FRONT. You can find the parts books for the L2800, L2900 and L3300 at Kubotabooks.com to compare before you decide and confirm my numbers.

They sell this part at TractorSmart.com is your online source for Kubota online parts. and Messick's | Dealer for New Holland, Case IH, Kubota, Cub Cadet and More | Online Parts, Sales & Service. and I'm sure your dealer can get it... but don't expect them to endorse the modification.

Good luck to anyone out there thats willing or eager to experiment with this!

 

[jfay]

I have a Grand L3300 circa 1996. The three point hitch is very smooth. No problems with jerky lift. I added draft control but that did not change the way it operates at all. Good luck on a fix for the later series tractors.

 

[GMtb42]

Hope you come up with a solution for this .
Will keep checking progress to see if anyone has any more info .

 

[Harvest Moon]

Thanks jfay, it's very interesting to me that over 12 years or more since it's
production, the valve in your tractor may be the answer to the L3400's position control problems.

At this point, I've got enough to put my theory to the test though, so I'm
starting another thread on the attempt. It should be easier to find for L3400 and L2800 owners.

http://www.tractorbynet.com/forums/kubota-owning-operating/135167-my-quest-grand-3-point.html

Anyone with an L2900, L3000, L3010, or L3300 who hasn't commented, please keep your observations coming. The more info the better.

 

[dooleysm]

Just found this thread and read through your other thread as well. Fairly interesting stuff. I've got an L3000DT, which I bought in the spring of 2005 from a guy in Kentucky. I think it's a 2002 model. It's got 346 hours on it as I recall. It's also got a FEL, not a Kubota, Big Bend or Great Bend or some similar model.

It's the only tractor I've driven in years and I am unable to watch the videos you posted. I've used all manner of 3 point attachments, auger, bush hog, rear blade, box blade, tiller, plow, and maybe some that I'm forgetting. I would describe the 3 point operation as very smooth, if you have a light touch. Slow and steady movement of the lever results in slow and stead movement of the hitch. Get too quick with the lever and the heavier attachments will bounce the tractor.

Best of luck to you in all your 3 point hitch experiments, I hope I have helped in some small way.