DK45SE hst Runs but non-responsive to pedal input

[kiotidavefl]

Hey everyone!

So I have a DK45SE hst that has around 500hrs on it. Its mainly used for property light maintenance and lately gets heavy boxblade use on my 5ac property. I run it primarily in M-range and keep my RPMS around 1500-2k when not on the PTO. It gets grease every 10-12 hours or so and it has had the 400hr service.

This morning, I was blading some fresh dirt around when after about 15 mins of light use suddenly the tractor became totally unresponsive to the pedal input. The transmission changes gears just fine, the oil had JUST come up to temp, all other functions appeared to work just fine. No matter what I did the pedals were not pumping hydro fluid through the HST. There were no obvious signs of hydro fluid missing anywhere and all levels appeared to be ok.

When i got underneath the tractor to start figuring out the problem, I saw that the actuator shaft that goes into the HST had sheared off right at the HST. Has anyone seen this before? What is the course of action for repair? Is there any sort of rigging fix I can do to at least get it up onto the trailer?

Thanks in advance! You guys are awesome

See attached photos

 

[xcgreene]

Bad luck. I wonder if the linkage was out of adjustment causing something to bind?

It appears as though you only need Item 81 in this here drawing.

Also see item #81 part# here.
Parts Finder Michigan Iron & Equipment Morrice, MI (855) 265-459


You may need to strip some framework off to get down to what was broken, perhaps you'll find an obvious cause during disassembly.



The price they give for Item 81 seems a little high for what it is, the term "control arm assy" makes me think the higher price is for all of the parts in that group. as in, all parts from 81 to 93, which you probably don't need.

I would call MIE, nolts, or whoever you like to deal with, and have a conversation. Best of luck, I hope this works out for you.

 

[kiotidavefl]

Thanks xcgreene for your advice. Im thinking youre right. That part definitely seems very expensive for what it appears to be, and I cant seem to find if it comes with anything other than just the shaft.

Im wondering if anyone has a shop manual on replacing that part before I go tearing it apart? Id hate to start with just that part only to find out there are consumables in there. Im gonna have to make this repair out in the field. Yikes!

 

[kiotidavefl]

Also, for what its worth, It didnt feel like anything was causing the pedal action to bind. I can actuate the pedals by hand without much resistance other than what comes from the dampers. Still trying to figure that part out.

 

[xcgreene]

To help determin your linkage adjustment was correct, have a look at this picture. Its from a Kioti EX machine, an Australian version of the DKse series. I have found it to be very accurate on mine. So I have no reason to believe these measurements would be different than yours, but use some common sense when applying these numbers to your rig.


Heres a view on the HST unit removed from the tractor housing. You can see much more clearly what cover needs to come off.




Note that the adjustment arm (#81) of course rotates with your foot pedal, which, in turn, moves the "Power piston" which actuates the swash plate of the HST axial piston pump.

Something to make note of while disassembling would be the spring placement against the fulcrum (item #82) its this brass colored item in the next picture below. Also note where that pin on the end of the adjustment arm (#81) goes into, to make sure you put it back in the correct spot of the power piston.



Its very hard to say what parts you may need at this point until it is apart. It may just be Item 81, or it may be a number of the seals and possibly item 82 as well. There is also the rare possibility of the power piston or swash plate itself has seized causing this to happen..... There is but one way to find out.



I'll tag along here in the forums and help where I can. I'm sure there are many others watching as well, who will lend you knowledge as you need it. Lots of great people on here.

 

[kiotidavefl]

Excellent info. Thank you so much!! I think I found a part of the problem. Poor installation of the snap ring on the output shaft. There was too much tolerance between the case and the ring, allowing it to rock back and forth.

 

[xcgreene]

Excellent info. Thank you so much!! I think I found a part of the problem. Poor installation of the snap ring on the output shaft. There was too much tolerance between the case and the ring, allowing it to rock back and forth.View attachment 565103View attachment 565105View attachment 565106View attachment 565104

good catch, that seems like a reasonable explanation. Any word on being able to order just Item 81 for maybe less than what seems to be quoted online?

 

[kiotidavefl]

The saga continues.

I repaired the snapped input shaft and during the test re-fit I was hoping to see some positive results be actuating the atm before fully re-assembling with gaskets and the pedal assembly.

I was NOT successful in that dream. Once the cover was re-installed I was unable to move the power piston that the input shaft indexes on. Neither forward or reverse would budge.

I attempted to manually push the piston up and down with a small pry bar and got maybe 1mm of movement. For giggles and grins I started the tractor to see if I was getting oil flow, and it appeared normal as it came from around that piston. Totally confused. Any ideas on how the power piston itself would be seized? Any blow up diagrams, (asides from the parts manual) or advice would be tremendously helpful.


Help!

 

[xcgreene]

The saga continues.

I repaired the snapped input shaft and during the test re-fit I was hoping to see some positive results be actuating the atm before fully re-assembling with gaskets and the pedal assembly.

I was NOT successful in that dream. Once the cover was re-installed I was unable to move the power piston that the input shaft indexes on. Neither forward or reverse would budge.

I attempted to manually push the piston up and down with a small pry bar and got maybe 1mm of movement. For giggles and grins I started the tractor to see if I was getting oil flow, and it appeared normal as it came from around that piston. Totally confused. Any ideas on how the power piston itself would be seized? Any blow up diagrams, (asides from the parts manual) or advice would be tremendously helpful.


View attachment 565738View attachment 565737Help!

Other than the parts manual as you stated, I have this.


The spool, Item 54 here, is what moves back and fourth inside the power piston assembly to actuate
the axial piston pump swash plate.

If the HST must come out to access this valve, the tractor must be split and hst removed.

But before you get too far into that, have a look at these two laymen flow diagrams, perhaps they could indicate a different problem with an easier solution.

 

[jjdward]

Other than the parts manual as you stated, I have this.
View attachment 565938

The spool, Item 54 here, is what moves back and fourth inside the power piston assembly to actuate
the axial piston pump swash plate.

If the HST must come out to access this valve, the tractor must be split and hst removed.

But before you get too far into that, have a look at these two laymen flow diagrams, perhaps they could indicate a different problem with an easier solution.
View attachment 565939
View attachment 565940

I hate to bring an old thread back to life, but I had the same issue with my DK4210se and it only has 60 hours on it. Were you ever able to resolve the issue?