L4330 slow 3 point hitch raise

[Joeboy]

Hi Guys,

New to orange talk and joined because of an issue I'm having trouble resolving. I am borrowing my Dad's L4330 GST for the summer for some work at my house. In return all he asks is that I fix the 3 point issue he's had on this tractor for awhile now. Easy right? He's owned this tractor since new and this is a problem that is slowly getting worse. I think its roughly a 2006 ish

The 3 ph will raise if I rev the engine up to around 1500 rpms or so but nothing at idle. The front end loader works perfectly and very strong, as well as the power steering. I am pretty mechanical and have read a few post online with people that had similar problems. I taken apart and cleaned about every relief valve on this thing with no improvement. I have located the power beyond line and appears to all be hooked up correctly with no kinks or issues with it. Oil appears to be in good condition and full. I have just replaced the spin on suction filter as well just to eliminate any potential issue. With a load on the raised 3ph is dosn't settle overnight so I don't thing the hyd cyls are bad.

My next step unless someone says different is to remove the top cover on the rear housing that controls the 3 point. Any more guidance? There have been many threads started on this issue but not a lot of them have been finished with what they did to actually fix the issue.

Thanks,

Joe

 

[100 td]

Kubota have a service manual covering this series of tractors as noted here.
https://www.messicks.com/part/97897-13000/l3130-l3430-l3830-l4330-l4630-l5030-service-m
There is a freebie manual here for the L3130, L3430, L3830, L4630, L5030 series tractors, for some reason the 4330 is absent, is there some inherent difference, or did they just forget to add this model number, maybe the 4330 wasn't released in this market, who knows.......

Maybe a different market, but you may be able to glean enough from it for yours?
Full illustrated parts layout should be here
https://apps.kubotausa.com/illustrated-parts/
From the manual above, it has 2 pumps, one for steering, GST and PTO, the other for 3pt, remotes and other (FEL etc.)
First thing I would check is the control lever to ensure it's not loose on the shaft etc., draft control if you have it, and feedback rod. Do you have remotes, are they all centered?

 

[Joeboy]

Shaft appears to be hooked up and moving the rod, I'll get a closer look at that when I get the cover off. Don't think it has draft control but does have a feedback rod which I have adjusted a couple different ways with no improvement. It does have factory remotes which I have unhooked for now and looped the circuits together.guess I don't know what you mean bycentered".

Thanks for the info!

 

[100 td]

Sorry, for some reason my post is missing the link to the free service manual
http://kubotabooks.com/AutoIndex/index.php?dir=Tractor%20Owners%20Manuals/&file=L3130%20-%205030%20WSM.pdf
Remotes centered means simply not in any position except the center neutral position.

 

[lugbolt]

Does the 3ph drop with a load on it when engine is off, load is "up"?

If yes-it's likely that there's an internal leak in the top cover assembly/aka "rockshaft" cylinder.

If no, there's likely an internal leak with the position control valve, the valve's o-ring(s), or possibly an internal linkage issue. My bet's on a sticking/stuck valve inside the position control valve if there's no other symptom such as leak down with a load placed on the 3ph.

 

[Joeboy]

Thanks for the service manual 100TD. Yes the remotes are/were centered

3PH doesn't seem to settle.

I removed the top cover last night and removed the piston control valve. I don't see anything obvious with the valve itself but I do have a better understanding how it all works. I need to check it out more.

What I did find is a chip in the housing where the oil enters the rear housing. There is still some surface there to seal just not as much. Could this be an issue? I hope my picture works.

 

[Witchgrass]

Thanks for the service manual 100TD. Yes the remotes are/were centered

3PH doesn't seem to settle.

I removed the top cover last night and removed the piston control valve. I don't see anything obvious with the valve itself but I do have a better understanding how it all works. I need to check it out more.

What I did find is a chip in the housing where the oil enters the rear housing. There is still some surface there to seal just not as much. Could this be an issue? I hope my picture works.

View attachment 37722

Any chance that you took some pictures with that top cover off? I’m curious what it looks like under there. Mine has different issues, but in same area.
Thanks,

 

[Joeboy]

Any chance that you took some pictures with that top cover off? I’m curious what it looks like under there. Mine has different issues, but in same area.
Thanks,

No but I can tomorrow

 

[Joeboy]

Alright I might have found it. There is a broken spring in the piston control valve. I ordered a new one this morning. It's supposed to be in Thursday. I will report back to tell if it worked or not. Maybe I will save someone else some time. Pics are of the broken spring, piston control valve and the bottom of the top cover where the piston control valve bolts to.

 

[lugbolt]

Spring sure can cause it. Now the other issue is, are there any tiny parts of that broken spring anywhere else in the valve?

 

[Joeboy]

Spring sure can cause it. Now the other issue is, are there any tiny parts of that broken spring anywhere else in the valve?

Maybe.... I will be thoroughly cleaning before assembly. Good this is the there is a small mesh screen before it enters back into the top cover assembly.

 

[Joeboy]

Alright guys, that was it. 3ph raises awesome at an idle now. Damn $6 little spring. The ol man will be happy. Big thanks to 100td for the manuals, they were extremely helpful!

 

[100 td]

Glad the manuals were of assistance and happy you got it repaired.

 

[Xyzer]

Joe! You still around? I have been dealing with the same issue! Same symptoms. Did learn if you dropped the bucket at high rpms it also raised faster. I'm pretty confident that I need to have that part handy when I dive in. You don't by chance remember the p-n thanks!
Dave

 

[Xyzer]

Hey all for future issues with symptoms post here. I had to tear into mine (3point valve) with same basic symptom. I found the little screen between the unloaders had dislodged and was not allowing the seat to set! Mine doesn't have a screen anymore. Thanks for posting your trials!