Kubota HST Problems

HST Problems

TPS Some of you fellas were talking about HST problems witih the Kubotas and did not give any specifics. I have visited with a lot of folks about them and have only come across one fella with a problem with his. I do have one and it is now 3 yrs old but only has 140 hrs on it. So can you give some specifics as to type of problems and about when they started occurring etc. also what type fluids were you running in them. Thanks for the information-TPS
Thurman Robinson BX24, Used Kubota UDT fluid, changed as book
said, pumps went out.
Bobby Faber Pumps and control valves went out, used the
Kubota UDT fluid. If you go back in the earlier post and maybe a page or two, most of the brake
down is HST.
Mike Shultze This may not be the same as Kubota tractors,
but at work we have parking lot sweepers that have Kubota engines and are HST. They use the
Kubota HST fluid from the dealer. We have had them stop going forward and reverse, engine
ran fine. Upon break down of the parts looking for the reason, we found the pumps would be
all scored up and seals blown. They looked like a piston that had been run without oil. We found
the same thing with the hydraulic motors the pumps provided fluid for. These hydraulic motors
were what drove the machine forward and reverse, there were also hydraulic motors of the same
make that drove the brushes and steering. All the hydraulic motors would end up looking the
same, but would not all go out at the same time. The hydraulic fluid was changed before the book
said to change, the filters looked like engine oil filters and had one for each hydraulic motor, and was changed when the fluid was changed. After a few years of this and not finding a good answer all we could think of is the hydraulic fluid wasn’t good enough, and didn’t have enough lubrication in it. These sweepers had much the same action as a tractor, low speed, forward and backward, sharp turns,
and 1/2 day running time. We finally replaced the main pump and all the motors and lines to
be sure no contamination would destroy the repair, we filled the system with the super UDT fluid and added STP to about a 10% mix, and that got us about twice the time out of the machines before the same thing happened again. The set up was not like a Kubota tractor, but all mounted on a frame and lines running to each motor from the pump and control valves, but did work on the same idea. I think all the components were Kubota manufactured, but would not sware to it. All 5 sweepers have been rebuilt in the HST area many times now, and are doing better at lasting with the extra lube in the UDT fluid. As for me, I would never have any HST product of any brand, and that’s from my experience on these beast.
Roger White I have a BX24 HST. had it a few years, got 394 hours on it, never had a problem. All I do with it is cut grass, nothing big and heavy,never been in a strain.
David Hamilton The HST problem is heat. The system builds high heat with a couple of hours use. Heat causes the UDT fluid to break down, and sooner or later the system fails. If you look at them closely you will find Kubota has tried to make them run cooler. If your use is small like cutting your yard once a week you will go for years and a lot of hours with no problems.
David Hamilton Forgot to mention, Kubota UDT fluid is the best you can get for now, it holds up to the heat better than anyother product. A gear drive tractor doesn’t build the tranny heat at all, it may get warm but not over heated.
Tom Bower Had my B7300 HST for 10 years now It is used every day and somtimes very hard. I use it for plowing,discing, mowing, and the front end loader is almost always in the pile, with the hydrostat mashed to the floor. I have a add on turbocharger on it that brought up the measured H.P. up from 13.5 hp p.t.o. to 21.5. I addad the turbo at 52 hrs and at the same time I added the power steering Kit. This tractor has 1600 hr on it right now, and I have never had one single issue with it. No breakdown with it whatsoever, ZERO. One nice thing with the hst is that the tractor can be a part of the family, as anyone could operate it. Mamma hooks up the little trailer and puts on picnic supplies and some folding chairs and off up on the hill for a quick picnic.
I have had nothing but perfect luck with my HST. So now that I said that , tommorrow the case will probably be busted I am convinced that a gear trans should last longer but the local kubota guy says he does 10 clutch jobs compared to maybe 1 HST job.
David Hamilton GOOD GOING Tom, I also have the B7300 HST and have never had a problem. The first HST I had did give HST problems. I figured out the heat problem from the tractors used at work,so with this B7300 I change the UDT at 50 hour intervals and that’s two or sometime three times a year, just to keep burned fluid down. Mine now has 2450 hours on it, and is use very hard. AS for the clutch replacement, it’s not the clutch or gear drive, it’s the driver. I also have a gear drive KUBOTA that’s almost 20 years old and never had a clutch problem, and never been adjusted, it still has about 2 inches free play as it should, and 3800 hours on it. Just to say what keeps them up is not loaning them or anyone but me using them.
Deal Gowers Just to let you know, I do have a Kubota that I use in land scaping. It’s a gear drive and yep it has a clutch. That clutch replacement is the driver. Mine has a whopping 4430 hours and is 24 years old, and never had a clutch replaced, but has had the clutch adjusted once. The other two Kubotas in my fleet are HST and one has been nothing but trouble, the other has done fine, but they are not but 7 years old and the bad one has 1510 hours, the good one has over 2500 hours. The name of the game for me is change the oil and HST oil often.
Lucas Jones I have two kubotas, one HST the other a stick. I love the HST I guess because i’m a bit lazy. However the stick has give less problems. CLUTCH replacenet? What’s that? The stick is 19 years old and never had any clutch problems. If I had to guess which one of my tractors would have the least problems and last the longest, it would the the old one with the clutch.
Funny thing, my neighbor has a old John DEERE which of course is a stick with a clutch, he’s such an idiot he takes out a clutch some times twice a year. The mechanic has told him over and over to take his foot off the clutch pedal but does he listen. NO he says it’s his tractor if he wants his foot on the clutch all the time he’ll do it.
Ron Johnson Guys I own a KUBOTA DEARLERSHIP. In my shop we see just about every thing broken that will break, some things broken that don’t break. Just to tell the truth, when the HST first came out we did have numerous problems. Kubota has ironed out most of them, still some to go, the over heating is still an issue if you don’t keep it clean. There are some HST large tractors that were designed to work hard and heavy. The small HST tractors were designed for light duty. That was to be the home owner with a large grass area to cut with a riding mower, but desired something better. The HST in this area (don’t repeat this) was designed so idiots could operate them safely. This small HST idea has took off like a rocket, involving small back hoe’s and the like. These small units do a very good job, the users love them, they go in tight areas and work hard, but the users are a bit rought on the small equipment and break them, we love it. As for the gear drive, they do hold up much better, give less problems. The clutch will hold up for ever, the user burns it out,
and we love it.
MPM Another key factor to longer life to HST transmissions along with good oil & filters is keepiing the rpm’s up high. Regulate ground speed with the transmission not the engine. High rpm helps to keep the oil cooler,and hyd systems work their best.
Chris I’ve got an hst bx24 that has about 100 hrs on it. Knock on wood- never had any problems that were tractor mfg related. Changed the fluid at 50 hrs per the manual and added a few cans of STP per almost everybody’s advice on this forum.
I have been disappointed with the backhoe, doesn’t have the snort I’d heard about. The fel is where it’s at, I now use my trusty old wheel barrow (that has all the blisters worn off the handles) to shoot at out back.
Larry Caldwell Typical HST problems are with getting the control pedal out of adjustment. Other than that, most of the problems are clutch related.

If you did your 50 hour service, replaced the UDT fluid and filters, and maybe cleaned the screens (if equipped) the HST itself should be fine. At 140 hours the tractor would still be under warranty, so check with your dealer to fix whatever problem you are having.
Tom Bower OOPPS!
Larry, I made a few posts earlier stating that I had Ø problems with my B7300 all the way up to 1600 hr. Wrong! Your post reminded me of when I first got mine in 1998 new, and the HST pedal damper was out of adjustment. It took to long to return to neutral. I had to push the opposite way to stop if I had to stop quick. A quick adjustment of the damper fixed it. took about 10 min to get it right.

About 3 weeks ago I got a lesson on how to spell “Damper” on this board when I was describing my little dealing with this! I forgot. Thanks Larry, tom

( i still think they should call it a “dampenerizicator”)
RON Tom, you can call it what you wish, it’s just
that no one will know what your talking about.
TPS Thanks for all the information guys. I have never had any problems with mine and glad to see for the most part they are trouble free even though there have been a few problems listed here-Thanks-TPS
Larry Caldwell As MPM mentioned, keep the RPMs up. That translates to using a lower gear, if you have a choice. The lower gear reduces the torque necessary from the hydraulic motor, and reduces the pressure required from the pump, as well as pushing more fluid through the transmission cooler. This is particularly important when you are digging with the front loader or pulling a heavy implement, like a full box blade. If you find yourself feathering the HST to keep from lugging the engine, shift down. It is very tempting to ease into the pile in mid range, because you can move faster with a full bucket. That puts a tremendous strain on the HST. Hey, it’s your tractor, and your repair bills. Drive it like you own it, and it will last a long time.

12 Comments

  1. DJ Johnson:

    Female weekend hobby use of HSTL3130 with limited hours, great equipment except for connection of PTO to mower or tiller. Arm strength can not manage strained position of working between tractor and implement, connection, holding connector inplace, etc. Any suggestion?

  2. Dan:

    L3710 rearend housing ripped apart at 3point hitch connection . tractor was not abused .is this a common design weakness

  3. Rick Bourget:

    I have a 2006 B7510 with 375 hours on it. I move loads of gravel,dig with the Woods bachoe,pull with a rake,dig stumps with back-hoe sometimes using the FEL to go down under the roots.I’m out in the hot sun and -30 degree Northern Ontario winter blizzards. This machine is an absolute Bull Dog.I got off the machine too fast and the seat switch shut the engine down.I stood on my head trying to figure-out this one.The HST pedal did not stop in the proper location. Now that I know this I just rock the HST peddle a bit to get it going.You guys have me concered about the HST. Maybe I should sell it now. Would break my heart knowing how well it works.

  4. sal the turk:

    KNOCK ON WOOD I HAVE A 1984 L3750 BUCKET BACK HOE WITH OVER 2400 HRS OF HARD WORK ON IT AND THE ONLY2 PROBLEMS I HAD WITH IT WAS THE STARTER MOTOR DEVELOPED A DEAD SPOT, I GAVE IT A SHOT WITH THE HAMMER AVERY TIME AND IT WANT GOOD FOR A WHILE , 2 ND PROBLEM WAS EACH TIME THE BACK HOE GO TO EXTREME
    IF YOU DID NOT HAVE THE STABILIZERS ETHER ALL THE WAY UP OR ALMOST ALL THE WAY DOWN WHAN YOU SWING BACK HOE FOR SURE YOU GOING TO BEND SOMETHING .AS FAR AS THE MOTOR IS KEEP UP WITH THE MAINTENANCE LIKE THE BOOK TELS YOU AND DO’NT OVER HEAT THE MOTOR, AND HYDRAULICS, DO’T RIDE CLUTTH ,AND BRAKES ,
    AND LOTS OF LUBRICANTS IN THE JOINTS AND BUSHINGS . GOOD LUCK. SAL.

  5. George Meyers:

    I have a L 2800 that the steering and the loader started acting up 2 weeks ago. the tractor is 3 years old with 120 hrs on it, after changing the fluid(second time since owning) and filters the problem is still there. It seems like a check vaule, because when turning the wheel it’s very tight and when I let off and turn it again it turns fine.
    Help

  6. caveman:

    i have had trouble with my bx24 i got about 150 hrs on it i had a hydraulic leak and o ring was bad i don’t think they have enough hyd pressure for the back hole and front bucket.i would like to find out to turn up pressure

  7. Harry Fike:

    Hello Kubota owners. I have a bx 1500. got it with 33 hours. now has 400 and this winter plowing snow i had a problem. the tractor would just quit moving. if i push the diff lock or put it in 4wd it would move. i just tore it down,,between snow plowing and lawn mowing time. i can’t find anything wrong in the gear department. i am puzzled and discusted.. anyo9ne got any ideas????

  8. Bob Saville:

    I have an old B7100HST. When mowing, I can use high road gear or low road gear and get the speed I want with the HST – which should I use?

  9. jinky santiago:

    Hi! I need to know if you have a KUBOTA Parts Catalog? Our Company needs to know the definition of the parts. Thank you!

  10. jinky santiago:

    kubota model is kh-60. Thank you!

  11. muleman:

    I have an L42kubota /the problem is the 3point pickup lever floats down when the tractor is running. the lift stays up when the tractor is off. any suggestions

  12. Carl:

    I need some parts for kubota G5200 lawn tractor,I am looking for a snowblower and a hood in good shape and an hour meter.

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