L series jerky 3 point

[Fordman1981]

Hey guys I had a moment of new tractor fever this weekend and went to look at a few tractors one being the L3800 I asked 2 dealers near by about the jerky 3 point if it was still an issue being the L 3800 and the L 3200 are new. One told me he had a guy bring one back with 7 hrs. on it cause he was so disgusted with the lift. I went to one of the dealers 30 mins from me test drove the L3800 and asked to put a blade on it. They said no problem it is jerky but not near as bad as some i have seen on here. The dealer told me that its the newest of the valve's and is suppose to be better but is still just ok to him. He said one fix for them is the predecessor 3010 valve i believe it was both dealers told me the same thing i hope i have the model right 3010 if not I know they said it was and earlier tractor model and the valve was a direct bolt in. Both dealers said Kubota would not pay for the swap under warranty being the new valve is suppose to be better but they would do the swap for $400.00 thats the valve and install and all. The dealer said its still not as smooth as a grand L valve but is 90% smoother. Once they told me what they would give for my trade in My NEW TRACTOR FEVER quickly vanished. Oh well my machine still looks new with 1100 hrs on it so it will suit me fine for yrs to come. Looking to add a few implements to get over the new fever Like tooth bar and a chipper. Hope this info helps you L owners out.:thumbsup:

 

[k0ua]

Thank you. That is the first dealer I have heard of that really would comment much on the problem or admit to a problem..

James K0UA

 

[weldermike]

Hi guys, new member here! About 8 weeks ago I bought a bran new L4400. Had absoluteley no problems with the hitch, and considered myself lucky after reading all the posts. It was smoothe as silk. When I bought the machine I wanted one rear remote on it, and my dealer told me they where on back order and when it comes in he would pick up the machine and do the install. Well I just got the machine back and and never paid it no mind while mowing, but went to do some back bladeing yesterday, and now am the proud owner of a jerky hitch. Could this problem be caused as soon as additional lines are added? Was never there before! Almost seems like the fluid is cavitating, air bound or something.

 

[General Lee]

Weldermike- I believe your L4400 and mine are the only ones at least on the forums that posted our 3pt hitch is jerky. I don't have rear remotes but my hitch was jerky since new. Its only jerky when raised slow, when I pull the raise lever up in one smooth motion it is smooth.

 

[weldermike]

Same here general, only jerky on way up, if you go in small incriments, but if I go up quick it is smoothe. Problem only showed up with new remote tho, so weird, gonna look into it.

 

[MessickFarmEqu]

Weldermike- I believe your L4400 and mine are the only ones at least on the forums that posted our 3pt hitch is jerky. I don't have rear remotes but my hitch was jerky since new. Its only jerky when raised slow, when I pull the raise lever up in one smooth motion it is smooth.

FYI... your L4400's are the same 3pts at the L10 and L30 series. Totally different designs than the smaller standard L's. If they are actually jerky, they are probably sucking air and a simple suction line needs replaced. Its more likly that your not adjusting your 3pt drop speed valves properly. If they are cranked open the entire way, its is tough to lower things slowly.

 

[weldermike]

Thanks for the refreshing news, had it in the back of my mind that the new problem would get worse. Not a hydroulic expert by any means, but seemed like an air problem. Thanks!

 

[General Lee]

FYI... your L4400's are the same 3pts at the L10 and L30 series. Totally different designs than the smaller standard L's. If they are actually jerky, they are probably sucking air and a simple suction line needs replaced. Its more likly that your not adjusting your 3pt drop speed valves properly. If they are cranked open the entire way, its is tough to lower things slowly.

That is good to know. Mine doesn't jerk on the way down. I've adjusted the 3pt drop speed to various speeds, doesn't seem to help the upward jerk. Any idea what line it could be? When I operate the loader, after things get warmed up I can smell Hydro fluid that is probably venting but where does it vent from? If the system is sucking air could that be why I am smelling hydro fluid as well?

 

[Chilly807]

That is good to know. Mine doesn't jerk on the way down. I've adjusted the 3pt drop speed to various speeds, doesn't seem to help the upward jerk. Any idea what line it could be? When I operate the loader, after things get warmed up I can smell Hydro fluid that is probably venting but where does it vent from? If the system is sucking air could that be why I am smelling hydro fluid as well?

My L3400 is exactly the same, Lee. Once it's warmed up, I can smell the hydro fluid as well, but usually only when I run the loader a lot.

The suction line angle is making me think... I know the L series are prone to the rubber suction line cracking and drawing in air. Would it not make the loader "twitchy" as well, or is that valve maybe less prone to cavitation than the 3 point?

The L3400 has a vent pipe under the seat from what I can see of the parts diagram, that may be where you're getting a whiff of the hydro fluid from on your L4400.

For the time it takes, I think I'll pull the suction hose off my L3400 and have a close look at it, maybe do a pressure test and see if it does have any cracks in it. The clamps are Mickey Mouse specials to begin with, they may get replaced with something better while I'm at it.

I've looked at two new L3800's this past week, both are jerky, although to a lesser degree than mine.

Sean

 

[Chilly807]

After looking at the suction line on mine, it's a classic case of a problem waiting to happen.

The suction from the pump (rubber hose with spring clamps on both ends) goes to a steel line, THEN through the hydraulic filter and finally a second steel line going to the sump.

I've noticed some aeration in the oil while running, it may be a problem after all.

Sean

 

[k0ua]

Sean, are you suggesting we replace our suction hose's? I have a new one, but my rig is just over a year old, and while it did set outside a few months before I bought it, it has been stored inside for over a year. (except for 100 hours)

James K0UA

 

[Chilly807]

What I'm thinking is that even if the hose isn't cracked, which has happened to a lot of L series tractors, the pump may be sucking some air between the rubber hose and the steel lines.

The filter in the suction side adds a lot of restriction, and air will go where fluid won't.

Why Kubota uses a rubber hose there, other than to damp engine vibration from cracking the steel lines, is beyond me.

The clamps aren't much either, simple spring type clamps with no way to tighten them. I'm going to pull the hose off mine when I get a bit of free time, make sure it isn't cracked. If I can find some better clamps, I'll try them at the same time and see if it improves the hitch action.

Neil Messick's comment about the suction line got me thinking about the poppet valves in the 3 point control valve that rely on a solid flow of oil to open and close them quickly. If the oil is slightly aerated, then it acts as a spring and has some "give" before the poppet will open. This MIGHT result in overtravel of the hitch before the feedback circuit can react.

It may be a wild goose chase, but if it is, it's a cheap one as goose chases go. A little time invested and a cup or two of UDT assuming I lose a bit.

It's possible that the valves have varying degrees of tolerance to air in the oil, depending on how close they are to being perfectly adjusted.

Sean

 

[General Lee]

After looking at the suction line on mine, it's a classic case of a problem waiting to happen.

The suction from the pump (rubber hose with spring clamps on both ends) goes to a steel line, THEN through the hydraulic filter and finally a second steel line going to the sump.

I've noticed some aeration in the oil while running, it may be a problem after all.

Sean

When I get some time this week, I'll look at my suction line and check things out. Its a new machine, been garaged since I've had it but did sit on the dealer's lot a while.

 

[Chilly807]

When I get some time this week, I'll look at my suction line and check things out. Its a new machine, been garaged since I've had it but did sit on the dealer's lot a while.

Even if the hose isn't actually cracked, the pump may be sucking air between the hose and the steel pipes.

Mine has 9.something gpm of fluid flow, when you think about it that's a fair bit of fluid to pull through an automotive type filter every minute, if it can get air it will.

Sean

 

[Chilly807]

I spent a couple hours mowing tonight, then had a look at the sight glass before shutting it down. I had a fair bit of air in the oil, the real question is: How much is normal?

Video didn't turn out that well, what's easily seen with the naked eye gets lost in the video.

Sean

 

[dancour]

Yes, my new L3200's 3PH is jerky too.

Being more specific, the 3PH will raise and lower completely very smoothly but if I try to inch it higher as when using my box blade, it jerks or bounces.

I was told that the L series is the economy level which has been scaled down to compete with the other brands like the NH Boomer to be at a price point that's competitive.

Apparently the L series does not have an "inching" valve that you would sure need if using a sickle bar mower. The better and more costly valve is included in the higher cost Grand L series I was told.

I'm still pleased with all the other Kubota L tractor functions and I'm backed by a super dealer.

The price was great for the L3200 and it seems to me a quality machine but my box blade work won't be as smooth as I'd like.

I imagine most guys don't hook up a box blade or mower and just enjoy the smooth operating loader, 4WD, HST, and power steering. So you won't hear from them until sometime later.

If anyone hears of a reasonable solution to the L3200's jerky 3 point hitch issue, please post.

PS I did have one set of remotes added to my L3200