HST Owners: Are there things to avoid?

dwelshans · Mar 6, 2012

This is not a spoof question (like don't run down your neighbors cat with your tractor

).

Rather, as a new HST owner (L4600), are there things you have learned NOT to do that overworks/overheats/potential damage type situations to avoid (such as extended time at idle, or working tractor below XXX RPM's)?

Or maybe better to ask things TO DO (run synthetic/change filters more often?).

Regardless...you get the gist of the question. Thanks for any input.

dodge man · Mar 6, 2012

The big thing is when climbing a hill is let off the HST pedal a little bit. Your reaction is to push it down further.

I run SUDT in my BX, I don't know if the L's take a similar fluid or if its different.

Adryan · Mar 6, 2012

Other question, who has experience running hydr. implements from other people/tractors? Won't the oil coming out of it cause problems with the oil of the HST? Surely not everyone knows what oil is in the implement

Rgds,
Adryan

Thomas · Mar 6, 2012

Pick the range..L,M,H.
Keep the rpms up..no lugging down.
When brush hogging rough areas easy on the travel pedal,you don't want to get the bunny hopps.

dwelshans · Mar 6, 2012

Adryan said:
Other question, who has experience running hydr. implements from other people/tractors? Won't the oil coming out of it cause problems with the oil of the HST? Surely not everyone knows what oil is in the implement

Rgds,
Adryan

Asked my dealer this question as I have a log spliiter that was driven off my Ditch Witch loader and it uses 30wt motor oil as a hydraulic fluid. He said to try and purge as much as possible from the hydraulic cylinder and hoses before moving over to my Kubota...but you don't need to get the last drop. Interested in what other options are from the Forum members.

namesray · Mar 6, 2012

one of the biggest things i would say about using a hst is to keep the rpms up close to rated range when driving the tractor. around 2000 on up. i usually run mine around 2300 all the time. my dealer told me you can take out the drive pump by driving around all day lugging on low rpms. it is also better for a diesel engine to not be lugged or idle too much.

as for the different hydrolic fluids in different attachments, i really don't know what could be done to minimize the different fluid transfer/mix. i have never known anybody to be too concerned about it. unless you are switching the same implement back and forth between different tractors with different types of trans/hyd oil all the time, i don't think it would make much difference. i think i read somewhere that kubota sudt is a 30 weight oil with just a special package of additives. like i said i THINK i remember reading that somewhere. in your specific case of switching the wood splitter from your older tractor to your newer tractor, maybe don't hook it up to your newer tractor until just before trans/hyd change time, then hook it up, run it for a short while to get the sudt in the splitter hoses, then change out the fluid in your kubota tractor. now your splitter is all filled with sudt and you are changing the tainted trans/hyd fluid out of the tractor, and putting fresh sudt in it. no wasted oil as you were at the change interval anyway. just a thought. good luck and enjoy your new kubota. they are great tractors!:thumbsup:

TripleR · Mar 6, 2012

Pretty much covered:

Pushing down on the pedal raises your gearing, so for added torque/pushing/pulling power, less pedal and more ground speed more pedal. If your engine starts to bog down, let up a little until you can maintain engine RPM and if this doesn't work change to a lower gear.

Keep your engine RPM's up enough to get good hydraulic response and power, they will run pretty high compared to a geared unit.

The HST is a pretty fool proof design and you aren't going to over heat it or hurt it by idling in gear, I rarely have mine in neutral.

You will get a gazillion opinions on oil changes and synthetic v dino. I go by the manual as to frequency of changes.

RobertN · Mar 6, 2012

Keep the fluid and filters changed as recomended.
If you are changing hydraulic implements, watch your fluid level
Don't lug it
Keep your coolers/radiators clean

When I got my used 3pt splitter, I purged as much fluid as I could out of it first. Then after hooking it up and running it in/out a few times with no load, topped of the fluid in the tractor.

I have friends with skid steers. When they rent breakers, trenchers ect, they just hook up and go... They have never had issues. Just guessing, but rental shops probably do not purge equipment...

nybirdman · Mar 6, 2012

Best advice I could give on the HST;use Kubota fluids and filters as long as it is in warranty(I still do),why take a chance.I won't use implements that have been hooked up to someone else's equipment.Check your screens often when bush-hogging.

k0ua · Mar 6, 2012

Pretty much what everyone else has said, I can only think of one thing to add, the 3 ranges in my opinion are used for the following things. range 3 or HI is only good for transporting the tractor on the road and preferably on mostly flat ground. Range 2 or MED is for moving around, with a load on flat to moderatley hilly ground. You can mow in MED if your ground is flat. Range 1 or LO is for all the pushing pulling and grunting you want to do in the steepest terrain. My opinion may be colored a bit by where I live (very steep). Also your tractor has more raw horsepower to work with than mine and that may change things a bit.. Good luck and I think you will really like it.

James K0UA

dwelshans · Mar 6, 2012

Appreciate all the input.

Thanks namesray:

"maybe don't hook it up to your newer tractor until just before trans/hyd change time, then hook it up, run it for a short while to get the sudt in the splitter hoses, then change out the fluid in your kubota tractor. now your splitter is all filled with sudt and you are changing the tainted trans/hyd fluid out of the tractor, and putting fresh sudt in it."

...great idea.

powerpace · Mar 7, 2012

Yep. What everybody else said.

MarkV · Mar 7, 2012

I would add to not change gear ranges while on a slope. There is a lag period and the tractor will free wheel if the brakes don't hold it on the hill. Don't ask how I learned that one.

MarkV

Ford tractor · Mar 7, 2012

Adryan said:
Other question, who has experience running hydr. implements from other people/tractors? Won't the oil coming out of it cause problems with the oil of the HST? Surely not everyone knows what oil is in the implement

Rgds,
Adryan

Practice "safe implement" You never know what you can get from un-safe fluid transfer -- :laughing: The HST's like a multi-vis 5w30 equivalent fluid (That's what's in SUDT), but many skid steers are full of straight 30wt hydraulic fluid. It won't kill your tractor, but if you thicken the fluid in the summer, it could give you issues in the winter.

There is one for sure 100% thing you should NEVER do. That is shift the range while moving. ONLY shift ranges with the tractor stopped. I think the book says stopped and clutch down but.... I don't always do that:ashamed:.

techman · Mar 7, 2012

Since hydraulics are my occupation, I guess I can comment.

There is little you can do to a hydrostatic to cause it any harm. Keep the fluids full and clean. The only "bad" thing is to stall the drive. As stated, if you lug and stall the hydro, all of the energy out from the hydro will go into heat. You can do this for short instances, but a prolonged stall will overheat the fluids and seals and cause potential damage. So if the torque is marginal, use a lower gear.

paul

InThePines · Mar 7, 2012

techman said:
Since hydraulics are my occupation, I guess I can comment.

...The only "bad" thing is to stall the drive. As stated, if you lug and stall the hydro, all of the energy out from the hydro will go into heat. ....

paul

I am not familar with some terms that many may understand, please tell me what stall the hydo means and how you know when it is happening and if it happens all at once or something you build up to or what. Thanks.

k0ua · Mar 7, 2012

InThePines said:
I am not familar with some terms that many may understand, please tell me what stall the hydo means and how you know when it is happening and if it happens all at once or something you build up to or what. Thanks.

Lets say you are hooked to a big tree with your drawbar, and you have some really good traction, and your running a lower rpm. You press the forward pedal, and nothing happens, the wheels dont spin, because you have excellent traction, and the RPM is low. The tree does not move, and like a dummy you just sit there with your foot on the pedal and nothing is happening. ( I know you would not do this) The engine is still spinning the hydro pump. and pumping energy into it, but the hydraulic motor is not moving and the fluid is just heating up. (this is what he warns against) This is similar to in an automatic transmission when you "power brake" by pressing the brakes, and the accelerator at the same time, the engine is spinning the torque converter and it is in a stall condition because the transmission cannot move due to the braking . For a short period of time this is not going to tear anything up. but it you just held the pedal, and hoped something is going to happen.... well...something will.

James K0UA

MHarryE · Mar 8, 2012

Like has been mentioned, keep the radiator and oil cooler clean. A hydro heats the oil a lot more than straight gear transmissions and the oil cooler is there to get rid of that heat. Use lowest gear that will get you the speed you want. You might be able to pull ok in a higher gear but the transmission pressure will be higher = faster wear. Back off on the pedal when the engine pulls down. That's about all there is to it except that the hydro is a piston pump and motor set and piston units thrive on clean oil.

oldnslo · Mar 8, 2012

With an HST, try to avoid sudden directional changes especially when travelling at higher speeds. This sudden change in direction can cause some very intense pressure spikes and also can potentially cavitate/starve the pump for oil for a brief time. This more prevelent in systems with hoses like skid steers but is still some thing to consider.

Also when cold, listen to your tractor. If the HST is screaming at you that means the oil is still cold and you cavitating the unit which results in a premature death. Slow down or let the tractor sit for a few minutes. HST's warm them selves via the charge pump loop.

BeezFun · Mar 8, 2012

Adryan said:
Other question, who has experience running hydr. implements from other people/tractors? Won't the oil coming out of it cause problems with the oil of the HST? Surely not everyone knows what oil is in the implement

My neighbor and I share his post pounder, it holds quite a bit of fluid. When I attach it I put the return line into a gallon container and work the cylinder until fluid color changes. Then I add my fluid to my reservoir to top off. When he gets it back he pours the fluid into his reservoir and pumps out mine into the gallon can and gives it to me. Lather, rinse, repeat. He's got a funny looking green tractor that uses a different kind of fluid, even though we're both diligent about changing fluids we felt better not mixing the different kinds of fluids.