L3400 3-point hitch adjustment

[LD1]

This is really frustrating.

Thats the whole point, the frustrating part is the deniability.

The L3400 has only been around for 7 or 8 years now and how many valves have they tried?????

That tells me they must have known it to be a problem.

And instead of wasting a lot of money, tech labor, customer confusion, why not just say "We know the valve is jerky, and nothing can be done short of replacing the whole unit with a better valve. We arent going to do it, but if you (customer) want the better valve and want to spend the money for it, thats your choice. But dont waste your time or your dealers time. Because nothing can make it better."

An another really frustrating part is that there are dealers on here (kubota dealers) who refuse to participate in these threads to shed some light. All they (those dealers) will say is that the havent seen hardly any with a jerky hitch. And the few they have seen were corrected 100% by adjusting the valve, without giving any details at all.

And maybe that is the case with the newer valves. who knows. But how many L3400's were sold with the older valves like mine that CANT be adjusted to correct the problem because they lack the "taper part" on the spool.

Not sure where the L3400's started, but mine is SN 61xxx. So I am guessing thousands out there with an in-curable jerk.

 

[kubotacres]

I'm curious since mine has been fixed, if I would have issues, IF i decided to purchase a FEL...However I have the newer valve on the L3200. I don't plan on buying one, but just curious.hmmmmm

 

[murphy1244]

How much is a new valve?? Just asking..

 

[LD1]

I'm curious since mine has been fixed, if I would have issues, IF i decided to purchase a FEL...However I have the newer valve on the L3200. I don't plan on buying one, but just curious.hmmmmm

The issue with the FEL effecting the 3PH is due to the dynamic balance. When in dynamic balance....ANYTHING that changes pressure or flow effects the hitch.

So to answer your question.....does the hitch move at all when going from idle to max RPM rapidly, or when shutdown, does the hitch drop at all??

It the answer to both is NO, then NO a FEL would not effect the hitch.

How much is a new valve?? Just asking..

Just a wild guess, but probabally $600-$800 for just the valve.

 

[kubotacres]

The issue with the FEL effecting the 3PH is due to the dynamic balance. When in dynamic balance....ANYTHING that changes pressure or flow effects the hitch.

So to answer your question.....does the hitch move at all when going from idle to max RPM rapidly, or when shutdown, does the hitch drop at all??

It the answer to both is NO, then NO a FEL would not effect the hitch.
.

I doubt I'll get a FEL for the my 3200. However my hitch doesn't drop or move at any occasion unless I adjust with the lever.

 

[timberland]

Thats the whole point, the frustrating part is the deniability.

The L3400 has only been around for 7 or 8 years now and how many valves have they tried?????

That tells me they must have known it to be a problem.

And instead of wasting a lot of money, tech labor, customer confusion, why not just say "We know the valve is jerky, and nothing can be done short of replacing the whole unit with a better valve. We arent going to do it, but if you (customer) want the better valve and want to spend the money for it, thats your choice. But dont waste your time or your dealers time. Because nothing can make it better."

An another really frustrating part is that there are dealers on here (kubota dealers) who refuse to participate in these threads to shed some light. All they (those dealers) will say is that the havent seen hardly any with a jerky hitch. And the few they have seen were corrected 100% by adjusting the valve, without giving any details at all.

And maybe that is the case with the newer valves. who knows. But how many L3400's were sold with the older valves like mine that CANT be adjusted to correct the problem because they lack the "taper part" on the spool.

Not sure where the L3400's started, but mine is SN 61xxx. So I am guessing thousands out there with an in-curable jerk.

My serial # is 57809 and I am not even confident that buying a new valve would fix the problem, at this point>

 

[Chilly807]

By the middle of the weekend I should be able to try a few more adjustments and see how good I can make it. We're supposed to get some more snow on Saturday, so I need an operating tractor by Sunday morning at the latest.

I know the older valves (Type 2) were considered worse than the newer style (Type 3). So, by trying to fine tune my Type 3 valve I'm hoping to both get mine to be better than it was, and to be able to give you guys some idea if it's worth shelling out more cash for a new valve, or even taking the tractor apart to be fine-tuned if you already have one.

In it's original condition mine was obnoxious, but livable. I just don't want to live with it if I don't have to.

I think the reason the L series has this problem is the 3-point design is flawed somehow, so a valve that's normally "good enough" isn't in this particular case.

Reducing the set-screw gap from 0.045" to possibly 0.035" should make a big difference in the amount the hitch jumps. If I can be reasonably sure it's stable and won't hunt up and down I'll leave it like that for a while and try it.

Moving the set screw from 0.026" gap (wild hunting) to 0.020" gap (almost perfectly stable but settling) isn't much of a change dimensionally speaking for quite a difference in performance.

I'm quite sure the adjustment range will have results that go from a) smooth but settling, to b) hunting and unstable, to c) jerky but not settling. I need to find the middle ground between the last two conditions.

If I'd known how much the hitch would settle and then jump back after using other hydraulics, I would have tried this setting before re-assembling everything.


Sean

 

[Caseyb1]

Really appreciate all the work Sean.

Casey

 

[Chilly807]

I don't mind the work, it's the kind of thing I like to get into anyway. I was really happy after the first adjustment and the lift was super-smooth, which turned into a rotten apple when I noticed the side effects that were part and parcel of that adjustment.

I'm still hopeful for a "silver bullet", but I also realize that the chances are getting less with every experiment we try. I should know something late today or tomorrow, I'm planning on taking it apart later today.

First move is to set the "spool joint to plate" adjustment to spec, it is 1 mm over the manual recommendations now. I think the only effect that will have is the lift will raise to a higher or lower spot in relation to the scale on the lever bracket, which will necessitate a re-adjustment of the feedback linkage.

If that's the case, then I'll try decreasing the set-screw clearance to less than the original setting to see if that makes the "jump" smaller when the lever is moved. It should to a certain degree, the limit to that adjustment option will be when the lift starts to "hunt" up and down by itself. I know it does it to a mild degree at 0.030", and it's violent at 0.026".

I doubt I'll get it really smooth, but any improvement is welcome at this point.

Sean

 

[k0ua]

Sean, You are doing great work... I have this sinking (and stinking) feeling that the people who have been told that their valve was adjusted to be non-jerky **might** have been lied to and that the dealer actually replaced the valve to ones like mine. I think if you can't find that sweet spot, I'm going to assume that those with "adjusted" smooth valves were duped into thinking that they can be.

Any one with an "adjusted" valve, willing to open it up and confirm the valve? and if it *IS* the original valve, take some careful measurements? THAT would be AWESOME!!!

That would be awesome to really know what was done and how it was done. This dealer I am working with thinks if I have the late model valve that it can be adjusted without replacement. He did ask for the serial number of the tractor first thing. Sean we all appreciate the work you and LD1 and others are putting in on this. It is a heck of a thing when we have to rely on customer's to gain knowledge of this problem and the possible resolution, instead of the manufacture being the one to guide us to the proper course of action. However it is not unprecedented. In my line of work, (working with phone and data products) This attitude is pretty common. (problems? what? we got no stinking problems!) I have over the years came up with fixes and work around's for several pieces of equipment myself that the manufacture initially denied and came out with a bulletin on later. Of course these "fixes" I speak of are software/programming fixes not tearing down a piece of machinery and learning how it works and coming up with ways to make it work better. I just don't have the skill and experience to do this. So again I applaud everyone's efforts and you guys are doing a great service to the rest of us in educating us about this problem and seeking a possible resolution. Thank You

James K0UA

 

[LD1]

First move is to set the "spool joint to plate" adjustment to spec, it is 1 mm over the manual recommendations now. I think the only effect that will have is the lift will raise to a higher or lower spot in relation to the scale on the lever bracket, which will necessitate a re-adjustment of the feedback linkage.

I'd save yourself the hastle because you are correct....all that does is set the implement to lever relationship. But changes nothing about how the valve operacts/acts.

When I first measured mine, I was shocked that it was 50.5mm instead of the spec of 47.5:confused2: But upon looking closely I seen it would do NOTHING to adjust it......but I did anyway, and set it to 47.5mm. The result was the implemet started to lift MUCH sooner. And ran out of travel too quick so I had to adjust the feedback rod per their direction. By adjusting until the relief kicks is, and then backing out two full turns. (or 2.5). I could have left it that way and no one would have been the wiser, BUT....I was out fo adjustment in the feedback rod. There are only 2" or so of thread for adjustment. So I put it back where it was @ 50.5mm and that left the "correct" feedback adjustment centered right in the middle of the threads.

With yours only being 1mm out, you probabally wouldnt need much feedback adjustment, but it really isnt worth the hastle knowing it wont help the situation at all.

PS...I hope you arent using RTV sealent everytime either. I found out quickly that I wasnt going to take the time to clean/seal everyting until I had it where I wanted it. I probabally had that top cover on/off at least 10 times. The onlything I re-assembled for testing whas the cover, banjo/hydraulic line, and the two plugs (PTO and N saftey??). I used a pin in place of the lever to test, and just heald the gear selector switch with my other hand. After the second time, I got tire of putting too much back together.

Good Luck once again.

 

[Chilly807]

I'll be at mine again shortly. I only used the sealant on final re-assembly, it doesn't leak much since there's no pressure at the top of the case.

Sean

 

[Chilly807]

I got it apart again, and tried tweaking the distance between the spool joint and plate to 47.5 mm, exactly in the middle of the specified range. As we expected, all that did was change the arm position in relation to the control lever. And the original setting, although out of spec according to the manual, puts the feedback nut almost dead center in the adjustment range. Strike one.

Next was the set screw adjustment to 0.033" gap. The hitch still hunted up and down by itself, although very slowly. Strike two.

Next I adjusted the set screw gap to 0.036", and although it didn't hunt, it was sensitive to any weight added to the hitch, namely me standing on the drawbar. It would edge up slightly, then settle and repeat after a few seconds. Also, instead of a jerk when raising, it was almost a chatter, several small increments. I'd planned to get it stable, then add about 0.003"-0.004" for insurance. It's hard enough to get apart that I don't want something that's going to be temperamental over temperature changes, slight wear, etc.
Adding 0.004" to probably 0.038" (to get it to a stable point) puts me back at 0.042", only 0.003" away from what it was when I started this project. Strike three...

I adjusted back to 0.045" and put it back together with sealant. I'll try it tomorrow, but I should have exactly what I had when I started, which although less than ideal is live-able.

I hope you guys have better success than LD1 and I did. I see now why Kubota wants no part of fiddling with these. I'd love to leave it at 0.006" gap as it was in the video I posted, it is simply super-smooth and controllable. However, I think the settling then jumping back when you use upstream hydraulics is worse than the rough raise I had before, and I still don't know for sure that it won't damage the valve long-term.

The results I got mirror LD1's for the most part. I may do some more research to see which valve is in the L3010, and what differences there are between them, but I plan to leave mine as is at least for the short term.

Sean

 

[sadie72]

Good news here, I think. Just got my L3800 back from my dealer with a smooth operating 3ph. Dealer and Kubota regional service rep took my valve apart yesterday and found it was not set to the appropriate suggested factory settings. I was told they made one adjustment and put it back together to find decent results. I am totally pleased with the performance of the vertical motion at extremely slow lever speed. I did notice that when curling and uncurling the FEL bucket the 3pt does lower about an inch and then goes back to original height after bucket curl. I personally don't feel this will hinder my intended use of the FEL and 3ph as I don't normally use both at the same time.

I asked my dealer what specifically was adjusted, what the original dimensions were and ultimately what it is set to now. He didn't have the numbers with him, but the Kubota rep wrote everything down. I should be provided with this data soon. Will keep you posted.

If I knew how to post a video, I would. Can someone help me with this? I have video of before and after on my iphone.

 

[LD1]

The results I got mirror LD1's for the most part. I may do some more research to see which valve is in the L3010, and what differences there are between them, but I plan to leave mine as is at least for the short term.

Sean

And you even have the newer valve and couldnt get it to work. Boy I'd sure love to hear from one of these dealers that "supposedly" adjusts them to spec and they magically work:confused2:

Good news here, I think. Just got my L3800 back from my dealer with a smooth operating 3ph. Dealer and Kubota regional service rep took my valve apart yesterday and found it was not set to the appropriate suggested factory settings. I was told they made one adjustment and put it back together to find decent results. I am totally pleased with the performance of the vertical motion at extremely slow lever speed. I did notice that when curling and uncurling the FEL bucket the 3pt does lower about an inch and then goes back to original height after bucket curl. I personally don't feel this will hinder my intended use of the FEL and 3ph as I don't normally use both at the same time.

I know you say you dont use the FEL and 3PH at the same time, BUT what you describe is the dynamic pressure situation that Sean and Myself had due to an overlap in valve timing. And (at least on mine) was RPM sensitive as well.

And (if you are like me) change rpm while using the 3PH at times.

So let me ask you to try this:

But your back blade (or even a mower on)....And then lower it to where it is "not quite on the ground" with the tractor at an idle. Now go to full rev and see if it moves.

Because like you, I though I could live with it because I dont use the 3PH and loader at the same time. UNTIL I found out it was RPM sensitive as well. And with my blade ~1" off the ground, (pretending like I was grading and would have put it in gear and reved up), the blade raised up ~3-4". ANd then when I let off the gas (like slowing to make a turn or gear change) the blade lowered again. THIS was unacceptable.

So....see if yours is sensitive to RPM change.

 

[sadie72]

Will try this tomorrow, for sure.

 

[sadie72]

Probably doesn't matter whether you have HST or gear, right? My HST tractor 3ph did not seem to move when I rev'd up from idle earlier this evening. But I'll pay more attention to this tomorrow and get back to you.

Are you suggesting the dynamic pressure condition could wear the valve out prematurely? I better get something from my dealer in writing about their adjustment for after the warranty period...

 

[teg]

...was just surfing the net and ran across this statement, thought I would throw it out for any comments?

"...Unfortunately this is not any easy adjustment as the top of the HST must be removed to gain access to the valve. The valve then needs to be removed to be adjusted, (via shims or springs, not sure at this time) then placed back into the tractor then tested..."

 

[teg]

...the reason the L series has this problem is the 3-point design is flawed somehow...

Just in case you missed this thread. http://www.tractorbynet.com/forums/...21524-l-series-jerky-3-point.html#post2537561

 

[teg]

Did someone want to look up the valve *I THINK* I got: It might be the valve from an L3010 Grand L, part # 31351-39604 but I never saw it or got any paper work to confirm this. Sorry, that's the best I can do.