Both the damper and spring are easily accessible. I think my next step is to remove the damper from the equation since (I believe) it's sole purpose is to control the return rate of the spring. This way I can see if the spring alone brings it to neutral on it's on any better or not. At least it will give me a next step. the movement needed to eliminate the creeping is pretty minimal so here's hoping I can identify an improvement between the damper/spring.
Is it possible to rebuild a HST damper?
- Thread starter 4lane
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Both the damper and spring are easily accessible. I think my next step is to remove the damper from the equation since (I believe) it's sole purpose is to control the return rate of the spring. This way I can see if the spring alone brings it to neutral on it's on any better or not. At least it will give me a next step. the movement needed to eliminate the creeping is pretty minimal so here's hoping I can identify an improvement between the damper/spring.
oldnslo
Super Member
Sounds like you are approaching this in a very methodical manner so confident you will find the root cause.
Just throwing out ideas or things to consider.
Is there a chance moisture, dirt got into that spring damper assembly and could be causing some extra friction from corrosion? May not take much to effect its ability to return home.
Best of luck on the search for the problem
Just throwing out ideas or things to consider.
Is there a chance moisture, dirt got into that spring damper assembly and could be causing some extra friction from corrosion? May not take much to effect its ability to return home.
Best of luck on the search for the problem
RNeumann
Elite Member
I’ve been watching this thread and wondering this very thing. It’s an easy test and will likely get you back to neutral. But I suspect it’s going to stop suddenly....like wear your seatbelt and hold on to the dentures fast!
RNeumann
Elite Member
If it turns out to be the dampener they make generic ones that may be less than the dealer. Maybe some more hassle though
oldnslo
Super Member
4lane
I suspect that Kioti has a description (translation) error on the two dampeners. I believe the one that has all the springs and appears rebuildable is the centering spring assembly while the other item is a sealed gas strut that is actually dampening or controlling the rate that the spring returns to center.
This why I asked if you could access these two items to confirm one is a spring assembly that just wants to return to a given position quickly while the other is more like a shock absorber and restricts movement
I suspect that Kioti has a description (translation) error on the two dampeners. I believe the one that has all the springs and appears rebuildable is the centering spring assembly while the other item is a sealed gas strut that is actually dampening or controlling the rate that the spring returns to center.
This why I asked if you could access these two items to confirm one is a spring assembly that just wants to return to a given position quickly while the other is more like a shock absorber and restricts movement
Cold weather has broken and I've finally had a chance to dig into this further by taking apart the assembly. The spring is actually just a gas damper, and the other one is just centering and controlling the rate of return. The centering damper seemed to act just normal.
However, the little gas damper acted quite odd and I'm not sure it's working properly. After you compress it, I would expect it to extend out on it's own like a normal gas damper, but it doesn't. Seems dead to me.
Here's a video of the gas damper after I've taken it out to test it. What do you think?
However, the little gas damper acted quite odd and I'm not sure it's working properly. After you compress it, I would expect it to extend out on it's own like a normal gas damper, but it doesn't. Seems dead to me.
Here's a video of the gas damper after I've taken it out to test it. What do you think?
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When it's attached it's not fully extended. It's about 2/3 extended. You can see in my second video above when it is in action (it's the black rubber one behind the centering damper in the front). If you put the pedal in reverse, the damper compresses. When you press the pedal forward, that damper extends.
That was my thought too. It's about $100. The original issue I'm trying to solve is the pedal not returning to center - the machine creeps when you step off the pedal. The centering damper seems to work fine; has good return rate, etc., and it's not an adjustment issue (you can adjust where the centering point is). And, I see his other damper looks like toast and am hoping that is the issue. But, I have to say, I don't quite see the relationship of how this damper influences the pedal return. I guess the pedal must need a certain amount of force from that damper, and without it the pedal somehow doesn't snap to center properly.
Peter 315
Super Member
Ya sometimes my tractor will creep when its real cold out then when it warms up its ok back and forth on the pedal for a bit
ericm979
Super Member
The damper is there so the pedals return to neutral gradually when you take your foot off. Otherwise the tractor slams to a stop like mine does. I have to let off the pedal a bit gradually.
The gas is in the damper to account for the space the rod takes up when the piston is fully seated. Some dampers just have atmospheric pressure air. There are reasons why that's not optimal in vehicle suspension but that's not relevant here.
If it is a gas pressure damper, and from the screw on the side that looks like a gas port it looks like it might be, then the other spring might be there to counteract the gas pressure. If the gas pressure is gone then the spring would be pushing the pedals past the neutral point. If it's easy to remove the spring you could try running it without to test this theory.
If there's a gas port the damper is might be rebuildable. Suspension rebuilders have equipment to put new nitrogen in shocks. But a rebuild would probably cost you about as much as the $100 for a new one.
The gas is in the damper to account for the space the rod takes up when the piston is fully seated. Some dampers just have atmospheric pressure air. There are reasons why that's not optimal in vehicle suspension but that's not relevant here.
If it is a gas pressure damper, and from the screw on the side that looks like a gas port it looks like it might be, then the other spring might be there to counteract the gas pressure. If the gas pressure is gone then the spring would be pushing the pedals past the neutral point. If it's easy to remove the spring you could try running it without to test this theory.
If there's a gas port the damper is might be rebuildable. Suspension rebuilders have equipment to put new nitrogen in shocks. But a rebuild would probably cost you about as much as the $100 for a new one.
The one with the screw on the side is the centering damper. That one certainly controls the speed of the return and centering between fwd/reverse. But this is not the damper with the issue. The one that seems to have an issue is the one that looks like a little gas strut. I believe it's the combination of this gas strut and the centering damper which returns the pedal to neutral gradually when you take your foot off. With both disconnected and the engine off, the pedal just flops back and forth with no resistance (not sure if this changes when engine is running). At any rate, it seems the gas strut is toast per this video:
s219
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The damper is not meant to return on its own. No damper is. So the behavior looks normal to me.
In a spring-damper system, all a damper is meant to do is slow the rate of motion of the "sprung" mechanism. It's up to a spring to do the motion. So the spring is what would center things back up (in this case, there could also be something internal to the HST).
As long as the damper isn't stuck, it moves freely, and it still provides resistance when moving, then it appears to be OK.
In a spring-damper system, all a damper is meant to do is slow the rate of motion of the "sprung" mechanism. It's up to a spring to do the motion. So the spring is what would center things back up (in this case, there could also be something internal to the HST).
As long as the damper isn't stuck, it moves freely, and it still provides resistance when moving, then it appears to be OK.
Hmm...here are my observations:
1. when engine is running, if I push the pedal forward and let go, it moves back to center but then stops before it gets to dead center keeping the tractor in motion
2. with engine not running, if I push the pedal fwd/back and let go it seems to come back to a center position (but you can't tell if it's actually centered or just off)
3. with engine not running and with both the damper (orange) and centering damper (blue) unattached,4the pedal just flops forward and back with no resistance
4. the blue centering damper just returns to a centering position from either position
5. the orange damper has resistance pushing in, when I let go it starts to push out on its own but then stops. There is still resistance to extend it by hand.
So, there is no spring in the system. Either the orange damper provides this by providing force when it extends (and I have something to fix), or the HST provides all the 'sprung' force to return on it's own (if so, I'm screwed).
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