HST pedal creeping - how does this system work?!

[4lane]

Interesting problem.

My CK30 is only the 2nd year of this model, and the only times I get slow return-to-neutral is when the tractor (and fluid) is cold. It is worse if the engine speed is low. I use UDT-equivalent THF, not a cheap hyd fluid. Fluid temp and type could be an issue beyond the more obvious damper and spring. I am at just over 800h.

Mine doesn't have anything to do with cold HYD fluid. Once it's warm it still creeps. This falls in line with it not being a HST issue and is instead related to the orange damper/blue centering spring and how they work together. If the orange damper were a bit weaker (but still strong enough to counter the centering spring's return) that may do the trick. Or vice versa, the centering spring being stronger...

 

[seaofblue]

Yes I saw this too, but while it describes the various components in play, it's still not clear where the issue resides. I did email with a Kioti dealer and got a good response (see below). Still nothing to direct me toward but helpful in eliminating the HST from the equation. That leaves me back to my test where I was able to stop the creep: by removing the damper but keeping the centering spring attached. It's like the centering spring is not strong enough to overcome the damper. I would jump at rebuilding the centering spring by replacing the springs but you can't just buy the springs, unlike what the parts breakdown suggests. So...still grasping at straws here.


<---- Kioti dealer ---->

"As hst tractors get older this Creep becomes something that most customers live with. We find a laundry list of things that can contribute to creep. Most likely is not the hst system as it is a swash plate and does not have effect on centering. Most often we find linkage issues, like worn parts and bushings are the cause. Dempers and spring issues are not unheard of and the hst lever bolt on connection at the swash plate shaft is also common. It could be spring tension related also. Lastly yes the resistance of the pistons in the swash plate area (or lack of ) in an older unit could in theory contribute to a limited amount of stiffness to this system."

Mine started doing it at 40hrs so it was a brand new tractor. Wasn’t expecting the first time it happen so I almost ended up in the ditch. Major safety issue.

 

[4lane]

Mine started doing it at 40hrs so it was a brand new tractor. Wasn’t expecting the first time it happen so I almost ended up in the ditch. Major safety issue.

It’s incredibly dangerous. I’m surprised the issue is just shrugged off. I guess they haven’t miraculously been sued yet for the tractor running over someone when no one was on it.

 

[seaofblue]

It’s incredibly dangerous. I’m surprised the issue is just shrugged off. I guess they haven’t miraculously been sued yet for the tractor running over someone when no one was on it.

Mine does it when the engine is warm or cold. Seems worst when it is cold and the fluid is thicker. It also seems worst when the tractor is in a higher gear. And it always does it when the HST is under a load. I love the Ck 3510 but I’m not liking this issue at all. I have reached out to the dealer and hopefully kioti can make it right.

 

[Looking4new]

Mine does it when the engine is warm or cold. Seems worst when it is cold and the fluid is thicker. It also seems worst when the tractor is in a higher gear. And it always does it when the HST is under a load. I love the Ck 3510 but I’m not liking this issue at all. I have reached out to the dealer and hopefully kioti can make it right.

Don't hold your breath.

 

[4lane]

Interesting problem.

My CK30 is only the 2nd year of this model, and the only times I get slow return-to-neutral is when the tractor (and fluid) is cold. It is worse if the engine speed is low. I use UDT-equivalent THF, not a cheap hyd fluid. Fluid temp and type could be an issue beyond the more obvious damper and spring. I am at just over 800h.

From my view, the blue centering spring is slightly too weak. Since a replacement is $400+, and you can't just get replacement springs, I'm considering disassembling mine, stacking some washers on the spring stop to increase the spring preload in an effort to make it stronger than it is currently.

 

[dfkrug]

From my view, the blue centering spring is slightly too weak. Since a replacement is $400+, and you can't just get replacement springs, I'm considering disassembling mine, stacking some washers on the spring stop to increase the spring preload in an effort to make it stronger than it is currently.

Sounds like a good experiment. You may also want to try a total spring replacement with a stiffer, non-Kioti spring. Pls report on how it goes.

 

[4lane]

Sounds like a good experiment. You may also want to try a total spring replacement with a stiffer, non-Kioti spring. Pls report on how it goes.

Exactly, that was my initial thought, but determined that getting an accurate compression rate might be difficult. And easier to just stack some washers...

 

[seaofblue]

Exactly, that was my initial thought, but determined that getting an accurate compression rate might be difficult. And easier to just stack some washers...

So I ran my tractor a long period today. Pretty much all day. I usually don’t have opportunities to do that. It’s usually for no more that 2 to 3 hours at time. The creep had completely disappeared by the end of the day. I mean I understand about fluid viscosity but I would think that 2 hours would be long enough for any fluid to warm up.

 

[seaofblue]

So I changed the damper and spring out today. Didn’t help. Still a creeper.