Is it possible to rebuild a HST damper?

[4lane]

My Kioti CK30 HST continues to creep forward or backward when you let off the rocker pedal. It is dangerous! There is not much to address the issue except for the pedal damper, so I am planning to pull it, and the return spring, to investigate more.

The damper looks like it will easily disassemble. Does anyone know if those things can be rebuilt?

 

[Billrog]

I don't think it's the damper the transmission is most likely the problem. Mine was replaced 3 times on warranty with supposed up grades and still creeps until the oil is good and warm.

 

[s219]

The damper is a fairly inexpensive part, so if that turns out to be the culprit then you may as well just replace it. I doubt they are meant to be rebuilt.

 

[4lane]

Each part is $350. Not interested in paying $700 if I am able to rebuild/improve it.

 

[4lane]

Yeah thats what I am afraid of - I have read similar stories. Mine is getting worse and warm oil is no better than when it is cold (if not worse). It REALLY irritates me and I find it super dangerous. I am surprised it hasnt been a bigger liability for Kioti that they are forced to address.

 

[oldnslo]

4lane
Are you experiencing any other problems with the HST like loss of power, speed, etc.

Does it always creep in the same direction or change depending on which direction you where traveling?

If no other problems I would start investigating all of the control linkage to see if anything is binding, possibly loose and slipping on shaft etc. Example In cold weather the grease on the pivot points on my Branson can cause creeping

HST by design want to return to close to neutral it only takes a minimal amount of linkage binding to prevent the linkage from returning to Full neutral there is usually some form of mechanical locator for neutral this can be external or inside the tranny housing

Do you know if the linkage directly controls the swash plate or does this model have a pilot control system

Direct linkage typically rotates approximately 18 degrees with some force required usually a little easier to maintain neutral position

Pilot style can also have rotating lever but typically require much less force to operate

Both styles of control should have some neutral adjustments.

My Branson has neutral valves built in to provide some dead band of pedal movement vs tractor movement not sure if Kioti has this feature or not.

Does Kioti provide any detailed parts breakdown for the HST and related linkage?

Damper might be rebuildable but not sure

 

[s219]

Hmm, must be different than the damper on other HSTs -- the Kubota damper used on many models is only $85. All it does is control the rate of return of the speed control treadle back to center.

 

[hosspuller]

Check the pedal linkage. Friend's Bobcat tractor had similar problem. Linkage at foot pedal was bent out of shape. A little bend back and creep was fixed.

 

[CalG]

I have an older Kubota B7200 HST. The dang thing will not settle into an un-moving condition when taking the foot off the HST pedal for love nor money. It's either creep forward, or creep reverse, no matter how I play with the pedal. A real annoyance when hooking up implements!
I've gotten into the habit of putting the transmission into Neutral when I need to get off the tractor! Sometimes I even set the parking brake.

The bigger issue with the HST damper is that letting off the "go pedal" results is such an abrupt stop that the tires skid and the tire chains scuff up the pavers. For that fix, I would like to discover a rebuild option for the damper.

That deficiency is not worth $85 though, plus all the time to R&R.

I suppose I will just live with it... Have done so thus far,

 

[aczlan]

The damper is a fairly inexpensive part, so if that turns out to be the culprit then you may as well just replace it. I doubt they are meant to be rebuilt.

If it's like the ones I have seen, they are a gas-filled shock, there is no way to take them apart and put them back together.
If you have the size, the force they need to put out and the end type, they are fairly inexpensive to buy a generic one, but good luck figuring out how much force they need to put out.

Aaron Z

 

[4lane]

There is no loss of power or anything like that. There are no obvious issues with the linkages either. It's only when moving in either direction, when you take your foot off the treadle it snaps back to almost neutral, but not quite. The tractor will continue to creep until you tap the treadle again to get it in a neutral state. I've read where other owners of this model, like Billrog, have had Kioti take it back and split the tractor to replace something - with varying results. Kioti has taken others and replaced the damper spring with a stiffer one - with varying results. The damper probably just tempers the spring's return rate so, on second thought, it's probably the spring not the damper that I would be playing with. I did adjust the spring a bit, but it didn't impact the 'step of treadle and doesn't return to 100% neutral' issue. Here are the parts in question that I can mess with.

 

[oldnslo]

4lane,
in looking on MIE parts break down there are 3 different part numbers listed for item 7. bottom of the same page shows what looks like an exploded view of item 7. I have studied the parts break down and question is this is the centering spring assembly and item 31 is the dampener. If link works it is the parts diagram that I am referring too. Parts Finder Michigan Iron & Equipment Morrice, MI (855) 265-459�

 

[4lane]

4lane,
in looking on MIE parts break down there are 3 different part numbers listed for item 7. bottom of the same page shows what looks like an exploded view of item 7. I have studied the parts break down and question is this is the centering spring assembly and item 31 is the dampener. If link works it is the parts diagram that I am referring too. Parts Finder Michigan Iron & Equipment Morrice, MI (855) 265-459�

Part 31 they call a demper assembly but it is just a spring. It looks to me this is the main return for the treadle and the actual damper just manages the return rate of the spring. Why the damper is $400 if it just manages the spring rate I do not know. The exploded view you see is indeed the damper, so it looks like there are some springs in there and it can be rebuilt. I am thinking my first step is to detach the damper so just the spring is connected and see if returns to neutral properly. (I will keep my seatbelt on for that test.

 

[Billrog]

This may help on my last tractor when it started to creep it had 3,000 hrs. on it and everything was loose with lots of play so I made new parts. On the Kioti I made all the adjustments out lined here but it still creeps when cold only.

 

[4lane]

View attachment 635448

This may help on my last tractor when it started to creep it had 3,000 hrs. on it and everything was loose with lots of play so I made new parts. On the Kioti I made all the adjustments out lined here but it still creeps when cold only.

I saw this over the summer and tried playing with the adjustments. I could definitely change the general positioning around neutral, but it made no difference in the treadle snapping back to neutral. Thanks for the insight into your history though. Do you know what they did under warranty those three times?

 

[Billrog]

On mine we checked the trans mission pressures in the port or ports under the seat they were not to spec so the reason for changing the transmission. Both were said to be up graded but didn't totally solve the problem shortly after being installed.

 

[4lane]

On mine we checked the trans mission pressures in the port or ports under the seat they were not to spec so the reason for changing the transmission. Both were said to be up graded but didn't totally solve the problem shortly after being installed.

Ah I see. Yes I was wondering if they changed something in the transmission, or the bearing going into the trans. I'm surprised someone hasn't gotten run over yet and sued Kioti.

 

[oldnslo]

4lane,
Not sure how difficult it is to access the two different dampeners but if possible can you disconnect one and operate them to see if they return to home position repeatedly. I suspect that one of them is more like a gas strut and will not return very well and the other should repeat position.

My old Kubota BX 1850 had a strut that looks very similar to your item 31. It did nothing for position, it strictly controlled return to neutral speed of the spring linkage assembly.

Other thing not easily done is to try and measure how much movement is required to go from creeping forward to reverse. This will provide some estimate of required repeatable accuracy of the centering mechanism. I suspect that it is not much travel.

 

[Leejohn]

On my b7800 Kubota it was the N cam bearing.

 

[radios1]

there should be a small dead zone between forward and reverse, which you may not have!..