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Help with hydro control lever, Sundstrand


Brettw

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Something just came up and I could use a little help.  Quite suddenly, the hydro control lever on the 17 GTH L became very, very easy to operate.  Forward and reverse has little resistance to movement, trans operates exactly as it should, movement is fine, forward, backwards, level of movement, etc.  In fact it moves so freely, the lever will not stay in place to maintain position and ground speed.  All the bolts at the linkages appear tight, and nothing addresses this in the repair manual.  This happened quickly, suddenly.  I was surprised at how easily the lever moved, gave it no more thought until it quickly went from speed towards neutral simply from the pressure on the spring holding resistance at the cam.  What am I missing?  What causes the resistance, or lack thereof, to keep the lever in position?

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Tension should be maintained  in the area where the lever goes through the frame down by the footplate. If memory serves, there are a couple of cupped washers that go together behind the short arm inside the frame..Should  also be a short pipe sleeve  that goes against the washers. Then a jam nut/ lock nut goes on the threaded end of the lever that goes through the frame, and how tight that is tightened determines how stiff or loose the lever moves.

Not exactly sure offhand about the order of assembly of those parts without a diagram in front of me.

Could be that locknut has loosened up. However , if it did,  that usually creates a few other symptoms too.

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Thanks, Sam.  One of the first things I checked. All is tight.  ( in checking and inspecting, I noticed the rubber coupler at the driveshaft is failing, headed off a future major potential problem, sometimes things happen for a reason, but I digress........)  But that would make sense, cupped washers that provide friction and resistance.  Why the sudden ease of movement I am not sure.  I will have to do a much closer inspection, but the nut had the patina of rust and grime on it appearing as though it had not moved, and it was tight with the wrench to confirm.

Edited by Brettw
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I have seen the pipe sleeve wear a groove into the back side of the short bracket before. There are also plastic bushings in the frame that the lever shaft slides through. Those can get worn and not fit tight also.

If I had to purely guess, I would say  perhaps a failed cupped washer..???...

You may have to take the whole assembly apart and see if  gremlins have attacked any of the components.

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10 hours ago, SmilinSam said:

If I had to purely guess, I would say  perhaps a failed cupped washer..???...

I will take that direction.  It happened quite suddenly.  And, the AGCO I just picked up had the opposite problem, everything was so tight it needed a good cleaning, so I just went through all of the moving parts and pieces on these and did not find any true adjustment.  So that is where I will start looking.  It's really nice to have the lever move so easily, sort of like power steering on a control, but obviously if it wont stay in place, that's an issue.  I'd never give up my cruise control, for power steering.666

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Well, in the complete process, this little item turned out to be fairly involved.  As stated, looking at the linkage under the tractor, I discovered a bad rubber coupler.  To replace that required moving the engine.  So, out of the engine bay she comes and gets a good thorough cleaning in the process, remove the tins, clean the starter Bendix, etc.  Rubber coupler replaced, disaster avoided.  Now, on to the control lever issue.  Sure enough, both cupped washers were installed "spooning", not facing each other and creating friction, must have just been a bit sticky previously, enough to hide the problem.  Carefully looking over all of the linkage also revealed another issue.  The spring buffer in the linkage has obviously been modified / tampered with, which would explain the linkage and lever issue and the washers being installed incorrectly.  

She'll all go back together today, and be back to 100%.  Thanks for the input all!

IMG_6226.jpg

IMG_6229.jpg

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2 hours ago, Brettw said:

Sure enough, both cupped washers were installed "spooning", not facing each other and creating friction, must have just been a bit sticky previously, enough to hide the problem.

I had one Sovereign enter my fleet like this.  I kind of liked how easy it was to move the lever.  Mine did stay in place though without changing speeds.  But like you, I changed it to the way it was supposed to be.  I wire wheel the inside of the Bellville washers & then coat the insides with low temperature grease.  They stay pretty lubricated & the handle moves pretty easy.  I'm sure all of us have had  one or two throughout the years that were pretty stiff.

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Don't you just love PO upgrades?

And thanks for posting the pic of the failed rubber coupler, never saw one before.  

 

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47 minutes ago, PhanDad said:

And thanks for posting the pic of the failed rubber coupler, never saw one before. 

Nor had I.  It wasn't separated all the way through, but it was bound to completely fail eventually.  Luckily I had a spare.

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The added washers to the spring in the linkage is a sometimes used fix for a problem where the spring compresses rather than moving the linkage in the hydrostatic transmission.  When this happens when you move the hydrostatic lever to change speeds the spring will first compress before moving the transmission arm.  Then later the spring will extend and the speed will increase more.  

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I have a somewhat similar problem with my 17gth-l. Though in my case I need to move the hydro lever almost half its travel before it starts moving the rod to the transmission. When I looked underneath everything was installed properly (cup washers facing correctly). However from what I could tell the machined rectangle on the end of the shaft was only engaging the other arm 1/16" if it was lucky causing the slop in the linkage. I tried tightening the nut more in attempt to try and "crush" the washers a bit for more engagement but all that got me was a lever that could barely move. Temporarily I flipped one of the washers and everything seems to work great but would love to know the proper way to fix this so my temporary fix doesn't cause more problems.

Thanks everyone for this forum existing, have learned a lot in my first few weeks of ownership of one of these machines.

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The shaft of the lever should be installed through the frame, with only the nylon bushings in place; no washer on the exterior, just the lever.  Internally (under the tunnel) there should then be the two cupped washers, then a bushing / spacer, then the slotted arm, and then a washer, lock washer and nut.  If there are other washers, or if the spacer is not the original part, that might be the problem.  The nut to tighten should bottom out when the slotted arm is fully engaged on the shaft.  The spacer and cupped washers create the friction.  If you can tighten that nut to the point of the lever hardly moving, either there are extra washers that don't belong, the shaft isn't fully passing through the frame, or perhaps a different or incorrect spacer has been installed?  If you remove the spacer and cupped washers, can you then fully engage the slotted lever to the shaft?  If so, I think I would grind a little off of the spacer, just a bit at a time, until the nut bottoms out and the lever is tight to the shaft, and the shaft moves with acceptable resistance.  

 

Just my thoughts, and what I have learned recently.  Good luck!

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I happen to have some detailed pics of what @Brettw describes above.  The pics were taken during the PS install on my 75th:  

IMG_5573.thumb.jpg.0155d43bd8bec006cc896c0f7aa8f07e.jpg

IMG_5579.thumb.jpg.e093a48d8b75b8fa23532b925e36913f.jpg

PS - If you click on the pics (several times), you should get another tab on your browser with only the pic with different degrees of "magnification".

Edited by PhanDad
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Thanks for the help everyone, I can get the slotted lever fully engaged by just flipping one of the cup washers and there are no extra washers installed. I think at some previous time a thicker bushing/spacer may have been installed that is throwing things off a little. I'll look everything over again later today and see how it goes.

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2 hours ago, GreenStratus99 said:

I have a somewhat similar problem with my 17gth-l. Though in my case I need to move the hydro lever almost half its travel before it starts moving the rod to the transmission. 

However from what I could tell the machined rectangle on the end of the shaft was only engaging the other arm 1/16" if it was lucky causing the slop in the linkage.

would love to know the proper way to fix this so my temporary fix doesn't cause more problems.

 

If I have a better control lever I replace it. On a couple of occasions I didnt have a spare.

On one occasion I  took a good center punch and peened on both sides of the  control bracket  around the worn areas,  flaring the sides out to fit tight around the worn end on the control lever stud. A little(very little) filing done to get it to fit tight.

On the other occasion I welded the worn areas on the stud itself up, then ground/filed down. Decided that the peening the bracket method was way better.

Edited by SmilinSam
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After a closer look and removal of the hydro control lever someone previously put a washer on the outside of the hole in the frame. I guess they thought that the lever shouldn't be directly against the nylon bushing, removed that, reassembled and everything is perfect, no slop and snappy response. Thanks again everyone for the help on the order of the parts stack and clear pictures.

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