So here I am doing some landscaping using box blade and front loader....taking out high spot and filling in low. Anyway I was using the loader and was cutting into the ground to curl the bucket to pop out a rock when all of a sudden ther was a "snap". When this occured I had the joystick in full curl position. Now the loader will not curl to the level position and remains 100% at the dump position. If I shut the tractor down I can push the loader to the curled position, as soon as I start the tractor the bucket automatically returns to the full dump position and seems to have pressure when the trractor is running. There is no leaking hydrualic fluid and the up down function works fine. The tractor is a Kubota L4330 and the loader is a LA 853. Any help is appreciated. Mike
Loader problem Cylider or Valve...Help!
- Thread starter Mike_VT
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Willl
Elite Member
Mike_VT said:
I'm going to say 'valve'.
I would also think about refraining from operating the tractor in this condition.
SPYDERLK
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Its one of your curl cylinders broken on the inside. same thing happened on my Mahindra 7520. Both cylinders were replaced with upgraded units under warrantee. It returns to dump only when you operate the stick when running, right? The problem is there is a blown piston seal or something else that allows major leakage past the piston. This means there is essentially equal pressure on both sides of the piston in both cylinders since they are in parallel. There is less area on the rod side so the force is outward -the rod extends to dump.
larry
larry
Mike_VT said:
Just to understand, you were in full dump position, you curled the bucket up to pop out a large stubborn rock and then the snap occurred. Right?
I don't think it is the cylinder. Here's why. The cylinder hoses can be disconnected when the tractor is running and no fluid will flow under pressure to them --> unless you move the spool valve off of neutral. If you really do have pressure on the bucket curling down when the tractor is running, it has to be due to the control valve. Possibly the spool valve broke (unlikely), or the centering spring broke (more likely).
Check it out.
Turn off the tractor.
Disconnect the hoses from one cylinder.
Start (or just crank with the kill activated) the tractor and see if you have fluid flowing.
If under warranty, take it back. If not, take the control valve off of the tractor. Take pictures of the hose connections and label the hoses as to where they go. Label the picture as to what each hose goes to. If you are handy - take the valve apart in a CLEAN area after you have CLEANED the valve. Else, take it to a hydraulic shop.
If there was no fluid flowing from the valve when the tractor was running, take the cylinders apart and re-seal.
jb
Egon
Epic Contributor
Check the joystick linkages.
I was poping out a rock with the bucket not quite in full dump probably less than 3/4 dump. The first thing I did was drive back to my shop and take the bucket and box blade off then removed the valve cover to see if I noticed any leaking of anthing that was obviously broken. Nothing. When I move the joystick to the dump position it appears to try to sent fluid as the hoses move, but no bucket action. The valve moves in and out freely and appears to return to center without assistance, but automatically returns to full dump when the tractor is running. When running I can push the bucket to return, but is is very difficult that is why I say it is under pressure. When off it is easier and I can hear the fluild pushing out of the cylinder. I am hoping this is covered under warranty...I bought the tractor on May 22, 2006 and took delivery on June 2nd. The loader is warranted for 1 year. Yikes, close call we will see. If it is not covered I will start by pulling the hoses etc. Mike
I would have to go along with SPYDERLK. I had something like this happen on a Massey once. I blew the piston seals out on one curl cylinder and it acted the same way. When you have the bucket in the dump position it puts alot of stress on the cylinders when you put pressure against the bucket. Cylinders are the strongest when the rods are retracted. It sounds like you blew the seals out or snapped the piston off the rod. Please let us know how you make out.
Dave
Dave
JerryG
Super Member
Mike,
Does it seem like the engine is pulling down? Like it is under a load.
Does it seem like the engine is pulling down? Like it is under a load.
Mike_VT said:
Hmmmmm......
From your further information, it may be a burst cylinder seal. Those are actually cheap to replace. But, it should be under warranty -> bring it in quick!
I am wondering if the "pressure" you were feeling was just the weight of the bucket naturally wanting to rotate down? If the seal was totally burst, there would be little to no resistance stopping it from that natural rotation.
Let us know what the real deal turns out to be.
jb
SPYDERLK
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jb, that part about the cylinders extending with the engine running and centered valve bothers me too. I think it is a cyl, but maybe in bursting, the fluidic shock damaged the valve as well. I cannot explain the full symptoms as described without a reach like this. Im not sure at this point that mine exhibited the centered valve extension. I am tho, haunted by a couple of nuance changes in mine that I believe are attributable to valve damage. When valving at full relief pressure - like if held to full curl and released - my valve does not return to center automatically as readily as it did before the break. ?Could it be imagination-just didnt notice before? MAYBE. Also, I now have a slow leakdown on curl that I didnt notice before. Another maybe-could be valve or new cyls or just didnt notice. This thread tho, is giving me a suspicion that there is some likelihood of damage thruout the curl circuit in this type failure. Either that or I have a gap in my understanding of the workings. Mike, please post the full diagnostic when you get it figured out.john_bud said:
larry
Willl
Elite Member
Mike_VT said:
After reading that, I'm changing my answer to cylinder.
Do the 'orange' tractors have quick-disconnect hoses that you could swap around to test ?
Dealer was closed today for the holoday. I am going to be the first call that they get tomorrow morning. (right now I have the buket off and I am just dealing with the weight of the quick connect plate)
With the joy stick at center I am unable to push the the bucket plate to what would be level when I move the joystick to level position I am able to push the fluild out of the cylinder. The puzzling thing is that as soon as I turn the engine the loader returns to full dump. One minute I think it is the cylinders and the next the valve. At this point who knows????
Jerry G good question, I do not have the feeling of load when the tractor is running.
Anyway I will let you all know how this turns out thatks for the input. Hopefully the dealer can get this in this week.
Mike
With the joy stick at center I am unable to push the the bucket plate to what would be level when I move the joystick to level position I am able to push the fluild out of the cylinder. The puzzling thing is that as soon as I turn the engine the loader returns to full dump. One minute I think it is the cylinders and the next the valve. At this point who knows????
Jerry G good question, I do not have the feeling of load when the tractor is running.
Anyway I will let you all know how this turns out thatks for the input. Hopefully the dealer can get this in this week.
Mike
SPYDERLK said:
larry, Just for comparison. I have left my loader with the bucket in level position about 5' off the ground for over 2 weeks and it only sagged a inch or so. No bucket curl down. With my 900# boxblade on the back the 3pt will sag about 1 foot in the same 2 week time. I was bored and wanted to check seal integrity...
Mike-VT, I am bouncing back to valve damage - with a side bet on a burst cylinder seal too! Dang but these long distance diagnosis are rough!
jb
RedDog
Platinum Member
Brought it to the dealer today and here is the diag. No valve problems, but both cylinders had problems. On one cylinder the nut completely stripped off the rod and on the other cylinder the nut was loose, as you would imagine this caused the malfuntion. The fix: the dealer has ordered two new cylinders and in the mean time they welded both nuts onto the rod and reinstalled the cylinders. Everything is working now and based on my discusion with the service manager the cylinders in this state should be fine for years to come, unless they start to leak. I plan on storing the new cylinders in my shop and using the fixed (welded) cylinders until they malfunction. From what I understand, from a friend at the dealer, one of Kubota's biggest issues is the with their cylinders. Thanks for all the help.
SPYDERLK
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Good! Youre lucky to be able to keep the old cylinders. They [Mahindra]wouldnt let me keep the broken ones. Can you, or anyone explain why the cylinders extended when you started the tractor with the curl spool in neutral. I assumed that closed off flow from the pump to the cyls.
larry
larry
SPYDERLK said:
First of all MikeVT, good to know you are back and running! It is a really odd ball failure, but ... By the way, those nuts are usually held on by 4-600 ft-lb of torque and some locktite. Guess there is a guy on the cylinder assembly line that wasn't paying attention.
As to why the cylinders would extend, that's easy. The pistong that has the seals wasn't attached to the rod, so the rod could move. Fluid was able to flow thru the piston's center hole so the bucket moved. Remember that both cylinders are connected together.
jb
SPYDERLK
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Quote jb: As to why the cylinders would extend, that's easy. The pistong that has the seals wasn't attached to the rod, so the rod could move. Fluid was able to flow thru the piston's center hole so the bucket moved. Remember that both cylinders are connected together.
Huh? Why did they take off and move when he started the tractor? With the valve in neutral should be no diff running or not.
larry
Huh? Why did they take off and move when he started the tractor? With the valve in neutral should be no diff running or not.
larry
SPYDERLK said:
Larry,
Can you see that with the nut from the piston off, fluid would go thru the hole in the piston where the threaded end of the rod is supposed to be? That fluid path would enable the other cylinder to move (it was still connected).
Why did it move when the engine was running? My guess is that the vibrations from the running engine and the weight of the bucket on the one remaining cylinder was enough to get it to move. There is several hundred ft-lb of torque wanting to rotate a bucket down.
Is any of this a 100% certainty? Naw, just my best guess from the facts stated and a bit of experience with cylinders.
Take care,
jb
Soundguy
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Engine vibration is my guess as well.. sinc ethe pistons were loose and allowing oil to bypass.
To the original poster.. with those sparecy;s' put some oil in the cyl. then compress..cap the compressed side to keep some oil in it..fill the uncompressed side with oil and then cap. Grease any exposed rod, and the wipe area.. grease yoke ends. Now, either wrap in have contractors paper.. or visquene and contractors paper and store. They should be good for years to come.
Soundguy
To the original poster.. with those sparecy;s' put some oil in the cyl. then compress..cap the compressed side to keep some oil in it..fill the uncompressed side with oil and then cap. Grease any exposed rod, and the wipe area.. grease yoke ends. Now, either wrap in have contractors paper.. or visquene and contractors paper and store. They should be good for years to come.
Soundguy
