I have a L4330 that needs a hydraulic pump. Realizing its a fairly new tractor called All States on hopes of a used one. They had one until removed it and realized it too was locked up and broke input shaft and messed up drive gears as well. Indicated that was a hard item to come up with. Hasn't been too many months ago a friends L3830 power steering stopped. Coupling in pump was stripped. I replaced the coupling. Pump appears to be the same as my L4330. Both seem to be a cheap design with relatively small shafts and only bushings instead of gears. Kubota is VERY proud of that pump. Aftermarket China pump is over $600. Is pump problems common? Neither of these tractors have any hours on them. Unfortunately it isn't a standard SAE pump. Close enough to AA to mount but oddball spline. Considered a crank driven pump. In the end price will be close to oem replacement but a better quality pump. Are pump problems common on L series?
L 4330 hydraulic pump broke/needed
- Thread starter johndear720
- Start date
Do you mean bushings instead or bearings?
You don't mention what the exact failure was in your pump, possibly similar to the used pump? Can you clarify for me and future readers please? What in your opinion failed first in your pump?
If you go aftermarket with a better quality pump, will you be able to remove the OEM gear housing which may also induce possible wear or failure due to the single bearing and side loading on the drive gear? Is there any hint of side thrust wear where the bearing sits or compression in the gear drive housing?
The main (front) pump gear took a bite out of the inside of the pump housing. It would appear it "galled" against the housing. Possibly from bushing wear. The pump only has bushings inside it. No bearings. You would think an $800+ OEM pump would have needle bearings not bushings. However with less than 1000 hours no reason for bushings to be worn either. So the pump locked up. It locked up while turning the motor with the starter. Had it been running at the time I'm sure the damage would have been worse.
For sake of full disclosure the tractor was a relatively low hour tractor that burned and was totaled by insurance. I purchased it cheap as a buy-back from insurance company. Took motor apart, cleaned, new rings and replaced the soft parts that melted. Paint was not burned off the motor or transmission. The hydraulic pump had been exposed to weather. It was taken apart and thoroughly cleaned. Parts polished back up. Just in the process of turning the motor with the starter getting injection pump bled and working the pump had primed and begun to pump oil. Injection pump had its issues so there was numerous sessions of chasing issues before to the point of actually starting motor. It was on that last time of OK ready to start it that the hydraulic pump locked up and choked the starter motor down. Upon removal the pump shaft had about 20 degrees twist, the drive gear was missing teeth, and upon taking pump apart found chunk of pump housing in the gears. The pump All States had was apparently in almost equal condition. No idea what would have caused either. Pump should last thousands of hours and this is a hundreds of hours tractor. Transmission was flushed, lines flushed, new oil, new filters, no sign of the pump eating anything. In theory anything it would have eaten should have gone into steering pump end first as the main suction is on that end and that little light weight coupling should have stripped between the two pump halves. Basically this is what happened to the 3830 i worked on for someone else. OEM filter that had never been changed began to come apart. That wasn't the case on this one.
The drive is an adapter housing. There is a drive gear on the back of the injector pump that drives the pump gear. Blocking off that drive will cause no issues as the injector pump shaft has bearings on each end. It should be happier as would have no side load induced by a hydraulic pump anymore.
My thoughts are to use the 18T 25MM splined end of the crankshaft to drive a pump. Much like earlier Kubota models did for adding a front end loader. Short jack shaft to a more standard two section pump. One with bearings inside it. It would mean replumbing but not that big a deal.
Plundering the forum it would seem numerous folks have had issues with pumps on machines with relatively low hours. I have other brands of tractors under the barn that have rolled over the hour meters with over 10,000 hours on them that have never had so much as an o ring replaced on a pump. Clean oil, regular service, good filters not much reason to wear something out running in oil. I don't abuse equipment either. Pretty sure in its short life this tractor took a beating. Judging by the broken 3 point hitch parts. Which has also always amazed me as how people do that? How do you break a lift arm?
Just curious from folks with many years history with Kubota if the hydraulic pump is a weak link. If so, its worth the effort to direct drive a name brand pump off the crank. If its rare then an OEM pump might could be stomached.
For sake of full disclosure the tractor was a relatively low hour tractor that burned and was totaled by insurance. I purchased it cheap as a buy-back from insurance company. Took motor apart, cleaned, new rings and replaced the soft parts that melted. Paint was not burned off the motor or transmission. The hydraulic pump had been exposed to weather. It was taken apart and thoroughly cleaned. Parts polished back up. Just in the process of turning the motor with the starter getting injection pump bled and working the pump had primed and begun to pump oil. Injection pump had its issues so there was numerous sessions of chasing issues before to the point of actually starting motor. It was on that last time of OK ready to start it that the hydraulic pump locked up and choked the starter motor down. Upon removal the pump shaft had about 20 degrees twist, the drive gear was missing teeth, and upon taking pump apart found chunk of pump housing in the gears. The pump All States had was apparently in almost equal condition. No idea what would have caused either. Pump should last thousands of hours and this is a hundreds of hours tractor. Transmission was flushed, lines flushed, new oil, new filters, no sign of the pump eating anything. In theory anything it would have eaten should have gone into steering pump end first as the main suction is on that end and that little light weight coupling should have stripped between the two pump halves. Basically this is what happened to the 3830 i worked on for someone else. OEM filter that had never been changed began to come apart. That wasn't the case on this one.
The drive is an adapter housing. There is a drive gear on the back of the injector pump that drives the pump gear. Blocking off that drive will cause no issues as the injector pump shaft has bearings on each end. It should be happier as would have no side load induced by a hydraulic pump anymore.
My thoughts are to use the 18T 25MM splined end of the crankshaft to drive a pump. Much like earlier Kubota models did for adding a front end loader. Short jack shaft to a more standard two section pump. One with bearings inside it. It would mean replumbing but not that big a deal.
Plundering the forum it would seem numerous folks have had issues with pumps on machines with relatively low hours. I have other brands of tractors under the barn that have rolled over the hour meters with over 10,000 hours on them that have never had so much as an o ring replaced on a pump. Clean oil, regular service, good filters not much reason to wear something out running in oil. I don't abuse equipment either. Pretty sure in its short life this tractor took a beating. Judging by the broken 3 point hitch parts. Which has also always amazed me as how people do that? How do you break a lift arm?
Just curious from folks with many years history with Kubota if the hydraulic pump is a weak link. If so, its worth the effort to direct drive a name brand pump off the crank. If its rare then an OEM pump might could be stomached.
Difficult, pump was working most likely working before removal? Why did it fail, galled out gear housing, possibly when re installed it didn't mesh? Was lubrication right up to the inlet of the pump when it was fitted? Hard to put down to general failure, but I can see a possible issue of the drive gear cocking slightly under load in the housing and therefore the contact of the small pump gear drive to the shaft splines constantly wearing due to that slight misalignment and slowly wearing the spines out until failure. Personally I would probably go with OEM, making sure the large pump drive gear hasn't been fitted 180 degrees/wrong side out, and carefully fitting gear housing and running without pump fitted.YMMV
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Lots of unknowns with this tractor. Bearing in the adapter housing was also replaced. If go with OEM pump gears will be new. They can't go backwards as won't fit. One might assume the pump housing had some damage from the fire that wasn't readily obvious. Slightly warped and once some hydrualic pressure developed wasn't adequate clearance in pump.
Before the failure happened you indicate it was taken apart, inspected and cleaned.
I further understand that the pump was never running at more than starter speed before failure occurred.
Adding my concerns on top of what 100 td has already told you:
My big concern in these situations is that something is wrong in the hydraulic system and the pump self destructed because its output was somehow dead headed.
Bushing pumps have worked reliably in machinery. It is after all, a pump which is a positive displacement designed for an open center system not a variable displacement one as used in closed center systems.
I do not have WSM for your model but looking at similar ones, their hydraulic systems are complicated.
Do you have a WSM?
Dave
I further understand that the pump was never running at more than starter speed before failure occurred.
Adding my concerns on top of what 100 td has already told you:
My big concern in these situations is that something is wrong in the hydraulic system and the pump self destructed because its output was somehow dead headed.
Bushing pumps have worked reliably in machinery. It is after all, a pump which is a positive displacement designed for an open center system not a variable displacement one as used in closed center systems.
I do not have WSM for your model but looking at similar ones, their hydraulic systems are complicated.
Do you have a WSM?
Dave
I have the manual. Oil is returning from the steering valve and lift circuit. All that was verified with air pressure. With the unknowns involved everything was taken apart to make sure no trash or bugs anywhere.
hi
somebody can tell me what the difference is between them
31351-76300
31391-76100
31391-76103
31391-76106
thanks
somebody can tell me what the difference is between them
31351-76300
31391-76100
31391-76103
31391-76106
thanks
North Idaho Wolfman
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Why do you want to know?
You would get better answers if you didn't lie about where you are at.
