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Old Tractor Enthusiest
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Discussion Starter #1
My BX23 with 1100 hrs has developed a steering problem. When attempting to turn right (cw movement of steering wheel) while mowing (w/o the FEL on) there is occasionally a delay between turning the steering wheel and the front end responding. It can take 2 or 3 times as many rotations sometimes before the front end steering cylinder responds. Obviously, this is not a good situation and it does it even when on level ground. The response to the left (cow) is as precise as you would expect with no issues.

This issue has gradually gotten worse over the last several mowings. Today, several times when I tried to turn to the right, it just didn't want to respond at all. If I did a jog with the steering wheel back to the left (ccw) and then quickly back to the right (cw) that seemed to help.

I rebuilt the front end steering cylinder about 2 years ago. Everything seemed fine since then until a couple of months ago when this steering issue started. Today it was by far worse than ever. I'm inclined to think a seal blew in the front cylinder. Any other ideas? I'm hoping it is not something in the steering box as that could be complicated at best to deal with.

Thanks
 

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I'll swag it's the cylinder seals again. I only say that as that is the usual culprit. You say you repacked them a couple years ago, do you recall the condition of the piston, was it pitted or have any bend in it?
Doing alot of dirt work?

I'm thinking out loud here and may be way off base. Are you running the new SUDT2?
Since it's synthetic it may get around those seals easier than the old SUDT or straight UDT.
My last 2 HST fluid changes was with SUDT2 and it seems the HST whines louder than what it did with the old SUDT. I tried to find enough SUDT to do my last change but couldn't find any locally so I don't have any facts to back up my all-to-rapidly-shrinking memory recall LOL..
I often thought of just going with straight UDT (20w) just for GP but when when the $$$'s hit the parts counter it's paying for the multigrade SUDT (10w20) as thats all I've ever run in my nearly 1000hrs. Perhaps one day I'll take the plunge to see if I get any improvement.

Anyways, the odd's of it being the steering controller are a whole alot less than the more common seals leaking under pressure in the steering cylinder.

Good luck
Dave
 

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Old Tractor Enthusiest
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Discussion Starter #3
I'll swag it's the cylinder seals again. I only say that as that is the usual culprit. You say you repacked them a couple years ago, do you recall the condition of the piston, was it pitted or have any bend in it?
Doing alot of dirt work?

I'm thinking out loud here and may be way off base. Are you running the new SUDT2?
Since it's synthetic it may get around those seals easier than the old SUDT or straight UDT.
My last 2 HST fluid changes was with SUDT2 and it seems the HST whines louder than what it did with the old SUDT. I tried to find enough SUDT to do my last change but couldn't find any locally so I don't have any facts to back up my all-to-rapidly-shrinking memory recall LOL..
I often thought of just going with straight UDT (20w) just for GP but when when the $$$'s hit the parts counter it's paying for the multigrade SUDT (10w20) as thats all I've ever run in my nearly 1000hrs. Perhaps one day I'll take the plunge to see if I get any improvement.

Anyways, the odd's of it being the steering controller are a whole alot less than the more common seals leaking under pressure in the steering cylinder.

Good luck
Dave

Hi Dave,

Thanks for your thoughts - I'm with you on each point. Not sure which SUDT I'm using. Replaced it about the same time as the steering rebuild with a jug of fluid from Messick's.

When I did the seal job the steering rod appeared fine. Nice and shiny with no nicks. At one point I did move a lot of dirt (12 dump trucks+) and also spread over 200 yds of 50/50 to reclaim about an acre of our property. But that was long before the steering overhaul. About all I've done since the overhaul is mowing, some mulch and snow work. What gets me is the steering is only leaking in one direction. If I recall correctly, the seals were the same on both ends and didn't have a symmetry to them - but that was 2 years ago and I can't remember what I did yesterday anymore....

Lacking any other ideas, guess I'll order another rebuild kit and do another rebuild. Guess there's always the chance I nicked a seal on reassembly and it's blown. I'm sure hoping it's not the steering box. Figure if something was leaking by the innards of the steering box the symptoms would be equally present in both directions.

Thanks much, Rob
 

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Did you fix this?,
You can figure out if it is the steering control valve or the cylinder by reversing the lines lines on the controller that goes to the cylinder and see if then problem switches sides or not. My guess it’s the centering spring in the controller gone bad.


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Old Tractor Enthusiest
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Discussion Starter #5
Did you fix this?,
You can figure out if it is the steering control valve or the cylinder by reversing the lines lines on the controller that goes to the cylinder and see if then problem switches sides or not. My guess it’s the centering spring in the controller gone bad.


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Thanks Orange,

Haven't fixed it yet. Just got the front cylinder rebuild kit in the mail yesterday. Good idea about swapping out the front hoses. Will give that a shot before I tear apart the cylinder.

Not familiar with the innards of the steering controller. Interesting thought about the centering spring. If that's the culprit, wouldn't the effect on the steering be in both directions? Or can that centering spring hang up in only one direction. Don't really want to mess with the steering controller. But gotta fix this issue. Just not safe to drive it much in the condition it's in.
 

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I'm sure you have checked this, but last year my steering on my BX2230D got weird. It had a super amount of slop in it. Turned out that the brackets that hold the steering cylinder to the frame had come loose on both sides! The left bracket was so loose that the cylinder ram had bent it! I had to remove that one and straighten it with a BFH and an anvil. Once I got them back on, (used Loctite on the bolts), the issue went away. So far the Loctite has worked perfectly. Also while I was in there, I found the ball joint seals were toast. I cleaned the ball joints, packed them full of grease and replaced the ball joint seals with a kit I found on E-Bay.
 

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If that's the culprit, wouldn't the effect on the steering be in both directions?

I think the spring can fail in one direction. After reading your post I became curious what kind of failure would affect only one direction. I have the shop manual and parts manual, so I studied both. It’s actually quite a complicated system at the detailed level.

Logic is as follows: First thinking about the steering cylinder, it has 2 chambers separated by a piston with a seal, and an outer shaft connected to the tie rod. If the inner piston seal was bad that would affect both directions since it’s needed to push either direction. If one of the outer seals were bad, that would cause one direction to not work, but you would see hydro fluid gushing out. You didn’t report that so I don’t think it’s your cylinder seals.

Then I looked at the steering box diagram. This thing is quit a complex device. It has 2 parts, a top section that controls the directional flow of the hydro fluid. This works buy having the steering wheel shaft when tuning apply torque to a sleeve around the shaft. This sleeve when rotated causes pressurized fluid to flow one way or the other to the steering cylinder. When there is no torque on the sleeve, the centering spring puts the sleeve back to its center position so there is no flow.

The second part if the box is a device that controls the flow of the pressurized fluid. There are 2 chambers that expand and 2 chambers that contract when you turn the wheel. The volume of the chambers determines how much fluid flows. So on full turn of the wheel is exactly the same amount of fluid flow independent of how fast you tuned the wheel. This device is completely symmetrical and works the same either way you turn the wheel.

So given those observations of on diagrams, which granted could be wrong, I concluded the most likely failure that is asymmetrical and not showing leaking at the outer cylinder seals it’s the movement of the sleeve controlling the hydro flow in one direction or the other. You also said sometimes you can get it to turn in the bad direction. That to me also indicates something wrong with the sleeve. So what i think is happening, something like is you turn the wheel in one direction, then stop, the centering spring is not returning the control sleeve back to center. So it won’t turn the other direction. The diagram of the spring not detailed. but it looks like it has multiple tabs.

The parts manual shows the steering box part number as one part, so you probably have to replace as one unit.

That’s why I suggested a way to isolate the issue to the cylinder or the steering box. Looking at my BX. it likes like it might be easier to swap the lines at the steering box than the cylinder for a test. Just take off the radiator back grill and the box is right there with the lines on the bottom.

Anyway I’m curious if this diagnosis is correct. Let us know what you find.

Wew, that was long.




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Old Tractor Enthusiest
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Discussion Starter #8
Orange,

Great note - thanks for the time and research you devoted to pulling that together. Follow what your saying on all points. I am still hoping that something is amiss with the steering cylinder and seals, but see your logic in that the issue may be the steering controller.

Going to swap hoses on the steering cylinder first and see what that does. If the situation reverses somehow, then it's the front cylinder - but I see where that may not be it. If that doesn't fix it, I'll troubleshoot the steering box and see what's going on. Sounds like it will be an interesting endeavor.

A few comments below in red keyed to your note. Thanks again.


I think the spring can fail in one direction. After reading your post I became curious what kind of failure would affect only one direction. I have the shop manual and parts manual, so I studied both. It’s actually quite a complicated system at the detailed level.

Logic is as follows: First thinking about the steering cylinder, it has 2 chambers separated by a piston with a seal, and an outer shaft connected to the tie rod. If the inner piston seal was bad that would affect both directions since it’s needed to push either direction. If one of the outer seals were bad, that would cause one direction to not work, but you would see hydro fluid gushing out. You didn’t report that so I don’t think it’s your cylinder seals. Correct - there's nothing leaking from the front end at all.

Then I looked at the steering box diagram. This thing is quit a complex device. It has 2 parts, a top section that controls the directional flow of the hydro fluid. This works buy having the steering wheel shaft when tuning apply torque to a sleeve around the shaft. This sleeve when rotated causes pressurized fluid to flow one way or the other to the steering cylinder. When there is no torque on the sleeve, the centering spring puts the sleeve back to its center position so there is no flow.

The second part if the box is a device that controls the flow of the pressurized fluid. There are 2 chambers that expand and 2 chambers that contract when you turn the wheel. The volume of the chambers determines how much fluid flows. So on full turn of the wheel is exactly the same amount of fluid flow independent of how fast you tuned the wheel. This device is completely symmetrical and works the same either way you turn the wheel.

So given those observations of on diagrams, which granted could be wrong, I concluded the most likely failure that is asymmetrical and not showing leaking at the outer cylinder seals it’s the movement of the sleeve controlling the hydro flow in one direction or the other. You also said sometimes you can get it to turn in the bad direction. That to me also indicates something wrong with the sleeve. So what i think is happening, something like is you turn the wheel in one direction, then stop, the centering spring is not returning the control sleeve back to center. So it won’t turn the other direction. The diagram of the spring not detailed. but it looks like it has multiple tabs.
Excellent explanation - can visualize what you mean. Will see what happens as I tear into things. Hopefully, if the spring is damaged, it can be replaced individually. A bit concerned about tearing everything apart and then being w/o the means to mow. If the BX is down for awhile, I'll just have to get out my trusty Gravely as backup.

The parts manual shows the steering box part number as one part, so you probably have to replace as one unit.

That’s why I suggested a way to isolate the issue to the cylinder or the steering box. Looking at my BX. it likes like it might be easier to swap the lines at the steering box than the cylinder for a test. Just take off the radiator back grill and the box is right there with the lines on the bottom.

Anyway I’m curious if this diagnosis is correct. Let us know what you find.

Wew, that was long.




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Old Tractor Enthusiest
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Discussion Starter #9
I'm sure you have checked this, but last year my steering on my BX2230D got weird. It had a super amount of slop in it. Turned out that the brackets that hold the steering cylinder to the frame had come loose on both sides! The left bracket was so loose that the cylinder ram had bent it! I had to remove that one and straighten it with a BFH and an anvil. Once I got them back on, (used Loctite on the bolts), the issue went away. So far the Loctite has worked perfectly. Also while I was in there, I found the ball joint seals were toast. I cleaned the ball joints, packed them full of grease and replaced the ball joint seals with a kit I found on E-Bay.
Thanks for the idea. It would seem if that was the case, the strange steering would be equal in both directions. In my case, the cylinder is properly secured.

Curious though... you mention repacking the ball joint seals. The OEM ball joints don't have any grease fittings on them. When the rubber seal gives, which it will eventually, about the only option I've heard of is just replacing the ball joint (circa $50 ea). What sort of seal kit did you find on E-Bay and how did you repack the joint without grease fittings? Did you find a compatible ball joint with a grease fitting?
I have found one way to extend the life of ball joints is to take an old bicycle inner tube and cut section out - put that over the ball joint when replacing it. The added protection helps prolong the life of the ball joint.

Had an unexpected trip to the emergency room last night. Hope to get to work on the steering issue today.
 

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Old Tractor Enthusiest
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Discussion Starter #10
Got a bit delayed working on the steering. Spent Friday night at the ER but back on the mend.

With all the rain this week, the grass was too tall to delay cutting. So I thought I'd give it a shot yesterday. The steering was fine the entire mow (1-1/2 acres) until the very end. After clearing our 450' driveway of clippings, when I tried to back the BX into the garage it refused to turn to the right (the same direction the symptom has always been). Tried several quick turns to the left and it would still not budge to the right. When in this state, when I turn the wheel to the right there is a very slight high pitches squeal. It's as if hydraulic fluid is bypassing something. The front tires vibrate slightly as if they are trying to turn right, but don't have quite enough pressure to do so when sitting on asphalt.

After several attempts at the "quick left and then try right" trick that worked before, I turned the wheel all the way to the left stop. That did the trick as the wheel would then turn to the right. I sat on the asphalt and went through this same routine a couple of times and each time when it stopped turning to the right, a turn to left stop would restore action again. It was almost predictably repeatable.

Orangetractor,
Based on the above experience yesterday, I'm inclined to think you're onto something with the centering spring and sleeve. Think it's still worthwhile to try reversing the front hoses to the steering cylinder. The challenge to that is that it appears this issue only happens after everything is hot after some extensive use. In hindsight I should have swapped the hoses yesterday when everything was hot after mowing for an immediate comparison. None the less, will plan to go out today and see if the steering problem exists today and if so, swap out the hoses and see what the impact is, if anything. If the problem is still present after the hose swap when turning right then the problem is the cylinder. If the problem has reversed itself, that would seem to confirm the issue is in the steering controller.

More to come - really appreciate everyone's thoughts on this perplexing issue.
 

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Old Tractor Enthusiest
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Discussion Starter #11
Orangetractor,
Took out the power steering module. Took it apart too... Wow, you weren't kidding about a lot going on in that unit. I took a few pictures for everyone's enjoyment.

Looked at the centering springs. There is a pair of them. Each pair consists of one concave spring and a mating flat spring made out of flat spring steel. They appear fine. Could not find anything inside that appeared worn. No burn marks, no scrapes, no nicks - nothing that showed an indication of being the reason for the odd steering.

I paid a lot of attention to the parts orientation when taking everything apart. Unfortunately, in the process of disassembling the unit, a single ball bearing and a small metal fork looking part fell out from someplace. They are visible in the lower right of the 4th picture. Very difficult to tell where they goes. If you can lend any guidance on where the ball bearing and metal fork go, I'd be most appreciative.

As shown in the pictures, the valve assembly has a lot of ports, holes and slits all over. It's really a marvel of engineering and metal fabrication. No wonder the retail price for a new unit is $909. Ouch. I looked up the parts list in Messicks and they only list the entire power steering controller as a single assembly.

If anyone can provide guidance on where the ball bearing and small fork part go in the steering controller valve assembly I'd greatly appreciate your guidance.

Thanks everyone.
 

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Holy crap that thing is complicated. And I agree, everything looks good, like it should still work. I bet it’s possible to put it back together and get it working.

Without seeing how it came apart and how those springs fit in I can’t really visualize how it went together. But my guess from looking at the parts, that the ball and fork are involved with the shaft applying torque to the sleeve when you turn the wheel. It looks to me like the ball is supposed to ride up and down the slot in the fork, which probably makes the ball engage and disengage with the sleeve, so the inside shaft will turn or not turn the outer sleeve. And when there is no torque on the wheel the springs disengages the ball somehow and the sleeve returns to its neutral position. I’m only guessing, so this could be complete BS, but that’s what it looks like to me.


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Old Tractor Enthusiest
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Discussion Starter #13
Well, the Internet sure is a wonderful thing. Looked at the manufacture's label on the side of the power steering module. Sauer-DanFoss OSPM 60 OM. Looked them up, found a great web site at Danfoss.com (guess they dropped the Sauer prefix - NFI) with tons of excellent product literature.

On the main home page scroll down to Service and Support and click on Downloads. Search on OSPM and it just so happens they have the manuals for the power steering unit used in the BX23. The valve body is the same, but the extension for the steering wheel is slightly different than shown on the web page. Not sure, but would guess it is used in other BX models too.

The power steering unit in the BX23 is a Sauer-Danfoss OSPM 60 OM. Just search on OSPM and several files will appear, including this one:

https://assets.danfoss.com/documents/DOC152886482744/DOC152886482744.pdf

The innards of the valve body assembly are exactly the same. The service manual even has a step by step process to disassemble and reassemble everything. I can't find anything wrong with the unit on my BX, so I'm going to try and put it all back together.

Crossing my fingers - don't want to do this again...
 

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In those diagrams there are what looks like 2 other spring loaded ball valves in the body, wondering if one of those is malfunctioning?


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Old Tractor Enthusiest
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Discussion Starter #16
Orange et all,

Just came in from getting everything back together (well... almost everything). I couldn't find anything amiss in the steering body at all. Even pulled out the pressure relief assembly and it appeared fine. Although, there's not much that can go wrong with it. Just a spring and small plunger - but thought while the whole thing is apart better not leave any stone unturned.

Got everything put back together per the instructions from Danfoss. And they were a lifesaver wrt that ball and the little forked piece. Although it's not clear what they actually do. Put a little petroleum jelly on the o-rings and lubricated all the moving parts in the valve body before reassembling. Man, you talk about delicate o-rings. The o-rings that seal the various large components of the valve body are about .030" thick by 3" in diameter. It would be real easy to muck them up during assembly.

Gave her a test drive and the steering works. I won't say it works "fine" until I get a few hours on it. Turned the wheels lock to lock on asphalt and rough concrete and there were no skips or dead spots anywhere. The feel of the steering mechanism felt normal. But at this stage I'm not sure what normal is anymore.

Thanks for your assistance and that from Dave as well. Crossing my fingers whatever it was is resolved. If it is fixed, far be it from me to say what the remedy is/was...
 

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Well hopefully you got it fixed. I've kind of been following this thread/saga from the beginning. It really didn't sound like the steering cylinder, though. By the way you described it, one of my early guesses was the steering box you went through (nicely done, BTW). The way you just described it acting, making a whine and the wheels chattering a bit as they struggled to turn, almost kind of makes it sound like an intermittently blocked hydraulic line.

When the wheels won't turn right, it's because the fluid can't get to the cylinder on that side. Turning the wheels left dislodges the blockage, and the fluid is allowed to pass normally (until the blockage moves again). You also mentioned that a "quick turn left" allowed you to go right again. Now, you have to go all the way to the lock on the left. Sounds like the problem is getting worse.

It's possible the issue went away after rebuilding the steering cylinder last time (and again this is all just a guess), because you moved and twisted and shifted the offending hydrauulic hose all over when you disconnected it, thus relocating the blockage until it broke free again. Just a guess, but it sounds like you might be running out of culprits, should the issue arise again in the future.

I've read a lot of posts by TUDOR (Bob), and this really does seem like the internally failed hydraulic hose he mentions from time to time.
 

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RDM,
Great to hear you got it back together. And thanks for the pics and details. I always wondered how the steering box worked. Looks like it’s actually a well made solid device. Maybe yours had some dirt in it someplace clogging it up. Let us know how it goes after you get some hours on it.

- orange


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Old Tractor Enthusiest
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Discussion Starter #19
Steddy/Orange,

Thanks guys - much appreciated. I anticipated the innards of the steering control would be full of some gunk. Nothing, nada. It was shiny and like new looking on the inside of the housing and throughout all the components of the steering control. The pictures posted before were after I wiped everything down, but there was no clean up of dirt residue at all. That surprised me.

I'm the second owner of my BX23. Bought from the original owner in Dec 2009 with 168 hours on it. I've replaced the hydraulic filter and fluid 3 times in 1000+hrs of ownership since Dec 09. So that's helped, but after 15 years and 1200+ hours, I expected some sign of wear inside. The main two parts of the control spool still fit so tight it was a delicate manipulation to get them back together. The edges of the various oil passageways are still sharp and crisp, just like you'd expect from a hydraulic spool. That too surprised me. One thing for sure, the steering control mechanism is one complicated piece of engineering. There really is a lot going on in there. The pictures don't do justice to all the ports, grooves, holes and passageways.

Could there be a pinched hose someplace, possibly. If that was the cause of the weird steering to the right it would seem it would happen more often. As mentioned before, I overhauled the steering cylinder about 2 or 3 years ago. It could still be that something has gone astray in there. If it acts up again, the steering cylinder is coming off for a complete inspection. I really don't want to pull the steering controller again. It was interesting to do once and see the inside, but that was enough to quell my curiosity. haha. If I never take the dash off again it will be just fine with me. I still have about 30 mins additional work to do to put everything back on and git er completely back together. Almost afraid to do so until I mow again. No doubt if I put everything back together, it will act up again. Just like putting the snow blade on before the first snow storm each year. Best insurance that the snow won't materialize.

If nothing else, found another good source of information on the Kubota BX. And since the internal components are not serviceable, if someone else has problems maybe this thread will help. Just remember - steering controller and DanFoss.com Had never hear of them before.

Will report back when after the next mowing or two after I get enough seat time to really test the status of everything.

Here's a few more pictures for future reference. Hope this helps others.
 

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Wow, you are the man, tackleing that controller is not for the weak LOL.
I agree on the WWW, the power of a million libraries from the comfort of our arm chairs.
Shame so many abuse it.

I've saved the ref you linked too. Wonder how much that steering controller is directly from them?

Hopefully it's either cleared or you inadvertantly fixed it without knowing it. I hate when that happens but then again I also like it too LOL.
 
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