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Tudor says it may not be a visible outside failure, but an internal defect that acts like a check valve inside the line.

He’s pretty good with oddball hydraulic issues like this. You might want to shoot him a PM to bring this to his attention.
 

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Old Tractor Enthusiest
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Discussion Starter #22
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.

Thanks much Volfandt.

It really is a marvel of engineering in a very tight space. When I opened the steering controller body and that ball bearing fell out, it bounced into the trash can nearby and I just caught a glimpse of it in the corner of my eye. I thought naw, wasn't anything. Then thought I better check. Sure am glad I did. You know the rest of the story...

Not sure how much of the controller is available from Danfoss. Based on the looks of their web site and the documentation for the controller, it may be a lot. Every single component is outlined on the parts listing in the service manual. Right down to the individual ball bearing in the check valve. No guarantee that I've actually fixed anything yet. But it's good to know there's a source out there if needed. Goes to show how important the OEM manufacturer's labels are down the supply chain. If that label was not not he steering controller there's no way to tell where it came from.

Makes me wonder... does Danfoss supply Kubota with the FEL and Backhoe control valves too? If so, we may be on to something here with wider applications (perhaps wishful thinking...)
 

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Discussion Starter #23
Tudor says it may not be a visible outside failure, but an internal defect that acts like a check valve inside the line.

He’s pretty good with oddball hydraulic issues like this. You might want to shoot him a PM to bring this to his attention.

Hi Steddy,

Yup - I've had some exchanges with Tudor in the past. He's very knowledgeable indeed and great to work with. Hard to imagine something inside the line being the culprit in this case, but no doubt strange things can happen in the world of hydraulics. Built a log splitter long ago using a unique design that splits wood in both strokes of the cylinders (uses two cylinders). Learned a lot about hydraulics on that project and some others along the way. Far from an expert by any stretch, but know enough to never say never about anything that involves pressurize liquid at 3000+ psi.

Going to see how things go with the next mowing or so and go from there. Crossing my fingers with reserved optimism.

Thanks...
 

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Wow, quite the project RDM, you got it apart and back together again quickly. Glad that it seems to be working, keep us updated on whether it starts having issues again. Can't beat the WWW for finding things normally!!
 

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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.
First hope you are healing well!

Repacking was probably not the right word, more like removing the old boot, cleaning the joint best I could of dirt, then filling the new boot with new grease, and installing it on over the ball joint. Did the same thing with the tie rod ends. Got the boots from an E-Bay vendor.

BTW awesome job with the steering controller. I know nothing about hydraulics beyond the basics, and the inside of that box is amazingly complicated.
 

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Old Tractor Enthusiest
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Discussion Starter #26
Wow, quite the project RDM, you got it apart and back together again quickly. Glad that it seems to be working, keep us updated on whether it starts having issues again. Can't beat the WWW for finding things normally!!
Thanks much will do. At this stage, I'll take all the luck I can get. If by some stroke of luck it's fixed, I can't even must a SWAG as to what I did to fix it. If the issue resurfaces, you'll all hear me screaming from afar w/o posting a word. haha
 

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Discussion Starter #28
First hope you are healing well!

Repacking was probably not the right word, more like removing the old boot, cleaning the joint best I could of dirt, then filling the new boot with new grease, and installing it on over the ball joint. Did the same thing with the tie rod ends. Got the boots from an E-Bay vendor.

BTW awesome job with the steering controller. I know nothing about hydraulics beyond the basics, and the inside of that box is amazingly complicated.

Feeling much better - thanks.

Gotcha re the "packing". Makes perfect sense. I was just hoping you found some ball joints with grease fittings. Never have liked the idea of having "permanently sealed' fittings. God made grease guns for a reason. One suggestion to add further protection is to slip a section of an old bicycle inner tube over the entire ball joint assembly. Provides extra protection from dirt and muck and still lets everything flex as it should.

Thanks for the kind words on the steering controller. You are spot on wrt how complicated it is inside. When that ball bearing and the little forked piece fell out, I could only think how screwed I was and that it was going to be a $909 mistake taking that assembly apart. (the cost of a new steering controller). After finding the Danfoss site with complete drawings I felt unworthy for having such good luck. Having it actually work when I got everything back together was icing on the cake (knock on wood as I haven't put it through a thorough test yet).
 

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Discussion Starter #29

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Discussion Starter #30
Mowed again this afternoon. The steering was fine for the first 45 mins or so. Then gradually the same issue started surfacing again and agin when trying to turn to the right. Argh... So, I'm wondering if this is something temperature related somehow? FWIW, I did check the hydro level before starting to mow. Was a tad low as expected since there was some fluid spilled during disassembly of the steering controller. So fluid or lack thereof is not the issue.

Won't have time to mess with it for a week or so. Looks like the front steering cylinder is coming off next. Some comments have been made about the hoses. If the front cylinder is not the problem, then the hoses are about all that's left to investigate.

Have to say this is starting to become a matter of principle... May give Kubota a call next week and see if they have any thoughts.
 

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Discussion Starter #31
Haven't been able to do much more troubleshooting of the steering for several weeks. Family emergency took priority... Not that's over with, I was determined to figure out what's amiss with the steering. It's gotten gradually worse and when I mowed last Friday it was worse than ever.

A couple weeks ago I talked to one of the service managers at Messick's. (they are great!). He suggested plugging both front lines. If the steering is "loose" then there's a internal leak in the steering controller. If the steering is tight (no leakage) then the issue is in the steering cylinder.

Got some flare plugs at Home Depot over the weekend and dove in tonight.... Despite thinking I had the right flare plugs, they didn't fit. I purchased 1/4" and 3/8" flare plugs, but it appears the fittings on the cylinders is actually a 5/16" flare. Don't think it's metric because a 11/16" wrench fit the flats snugly. Since I didn't have a correct flare plug, I just removed the entire steering cylinder. Does anyone know exactly what size the fittings are on the hydraulic hoses on a BX? I looked at the parts list on Messicks and the fitting size is not listed - just part number.

Disassembled the entire steering cylinder assembly. Already had a seal and o-ring kit, and intended to just replace everything. After exposing all the components I found what appears to be the cause of the funky steering. The main center o-ring was worn flat. The odd thing is it wasn't worn flat evenly. It was an an angle favoring a better seal when turning left. The o-ring was so worn it actually looked flat across the face exposed to the international wall of the cylinder. I couldn't get the left tie rod off, so I only replaced the end rod seal on the other end.

How can the o-ring wear so oddly? The only thing I can figure is that when I installed it during the last steering cylinder rebuild 4 years ago, the center rod o-ring got rolled into place in such a way that it was actually twisted during operation. This caused the o-ring to wear unevenly and the twist in the o-ring favored wear in one direction over another. This would explain the steering issue in one direction only. Checked the inside surface of the cylinder wall - nice and smooth - no scours or worn edges to adversely wear the o-rings. There was a little corrosion at both ends of the cylinder wall which I honed out with fine Scotchbrite and a dremmel with a wire brush. This is the area where the cylinder rod seals seat in place - so it's not exposed to fluid.

To help put everything back together smoothly, I dipped each o-ring in new hydraulic fluid and coated the interior of the cylinder before installing the rod. Paid particular attention to not rolling the new center o-rings into place. I carefully pried them over the lip of the cylinder piston. Keep in mind there are two o-rings in the center seal on the piston and the larger of the two o-rings rests on top of the smaller one and is the one exposed to wear.

Reassembled the steering column and put everything back together. Fired her up and after a couple of turns lock to lock the steering cylinder filled up and operated normally. Not going to declare success until I mow and heat everything up.

IMO using just an o-ring on the center seal is a weak link. There should be two wiper style seals on the piston similar to the end seals on the rods. Those seals are designed in such a way that the hydraulic pressure helps seal them around the rod. As they wear the hydraulic pressure helps "inflate" the seal to continue making a good seal on the rod. If Kubota used the same setup to seal the center steering piston, it would be far more reliable and better able to withstand wear compared to the o-ring based seal. Wonder if any of the newer BX steering cylinders were upgraded? Does anyone know?

Will report back after the next mow or two - assuming it goes well and the steering is fixed. If the problem surfaces again, I'll..... don't want to even think about that.
 

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Gotta give you an A+ on tenacity LOL...
If that wasn't THE problem it certainly was A problem.
Good troubleshooting.
Did you take any pics?

Dave
 

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Discussion Starter #33
Gotta give you an A+ on tenacity LOL...
If that wasn't THE problem it certainly was A problem.
Good troubleshooting.
Did you take any pics?

Dave

HI Dave,

Thanks for the A+ - haha. Didn't have much choice but to figure this out. I did take some pictures, which are below. The odd thing is I just rebuilt the steering cylinder seals in 2014. It seems excessive that the center o-ring would wear relatively so fast. I'm wondering if the center piston o-rings in the kit I purchased is not a OEM replacement. The slot in the piston is wider than the o-rings by about .050 (educated guess). No doubt there needs to be some clearance for the o-ring to compress inside the cylinder - it's a tight fit. However, if there's too much slop between the walls of the piston and the o-ring, the o-ring will work back and forth as you steer. This could explain the accelerated wear.


The 1st picture shows the steering rod with the old o-rings and seals just above it - the new o-rings and seals are at the top of the picture

The 2nd picture shows the two worn o-rings from the center steering piston.

If you zoom in (3rd picture), it may be possible to see how the larger o-ring is worn flat around the outside - and the wear is not square, which allowed it to still seal in one direction, but not the other.

The 4th and 5th pictures show the small hole that's in the end of the steering cylinder housing. This is very useful to keep the retaining ring from spinning when you try to pry it out. It has to be removed to remove the steering rod and end seals. Key to removing the ring is to pound the end seal in about 1/8" to take the load off the ring. There's a shoulder inside the cylinder wall to prevent the end seal from being pounded in too far. If you don't do push the end seal in, it's nearly impossible to flex the retaining ring out of it's groove.


I posted some of this back in 2014 when I did the last steering cylinder rebuild. As was the case then, the most difficult part of rebuilding the front steering cylinder seals is getting both tie rod ends off. The problem is with the steering rod - it only has flats on one end. Last time I got lucky in that the tie rod on the end with the flats broke loose first. That allowed me to get a wrench on the steering rod to keep it from spinning to break of the other tie rod loose.

This time I was not so lucky. The tie rod on the opposite end from the flats broke free first. I tried about everything I could think of to break the other tie rod free. Never could. Didn't want to try heat out of fear of damaging the tie rod that was still attached.

I took an old tie rod - removed the tie rod end, which has the same thread as the steering rod. Screwed in the tie rod and used the jamb nut to snug the end to the steering rod. Still could not break the other tie rod loose.

I tried using a band wrench to grip the steering rod - it just slipped. Tried a BIG pair of channel locks - ditto. Tried a small pipe wrench with tape wrapped around the steering rod - more slippage. Got even more aggressive and used a big pipe wrench - the steering rod just rotated (with absolutely no marring of the rod surface). Finally put it in my big bench vise - just kept spinning around.

I don't know what the heck Kubota did to heat treat that steering rod, but it is nearly indestructible. Normally a chrome finish on cold steel will fracture, chip and/or mare the surface when you put a wrench on it with teeth - not that steering rod. It became a matter of principle to break that other tie rod free. I was willing to destroy the steering rod to do so - but couldn't put the slightest nick in the surface despite the best efforts. To withstand the abuse it was subjected to, Kubota had to heat treat the steering rod before it was chrome plated. That's the only way to have a surface that resilient. I've worked with a lot of materials in my day, to include some fairly exotic chromoly steel - this took the cake.

The only thing I didn't do was grind down a wrench thin enough to get on the flats. If/when that tie rod needs replacing, that will likely be the next step. The other thing I may do is grind flats on the end of the steering rod that does not have them. The very ends of the rod stick out from the ends of the cylinder. Believe there is enough excess to put a couple flats on it to keep it from slipping in the future. Will ponder that some more when the time comes. Am also wondering if Kubota put flats on both ends of the steering cylinder rod on models after my BX-23. It does not make sense to have the flats only on one end. Wondered back in 2014 if this was a manufacturing oversight way back when it was made.

Hope the above helps someone else at some point.

Thanks, Rob
 

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Old Tractor Enthusiest
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Discussion Starter #34
Cut the grass and mulched leaves today. Absolutely no issues with the steering at all. Must conclude the center o-ring on the steering cylinder piston was the issue. Much relieved it's steering as designed now and that the issue was not the steering controller - $$$.

Appreciate everyone's support as this played out. Hopefully this thread will help someone else in the future.
 

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Guess I was wrong about the steering control causing your one way problem. I never would have guessed in a million years that the center seal would fail in one direction. Sorry to have mislead you on that months ago. Gland you got it fixed.


Sent from my iPad using Tapatalk
 

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Discussion Starter #36
Guess I was wrong about the steering control causing your one way problem. I never would have guessed in a million years that the center seal would fail in one direction. Sorry to have mislead you on that months ago. Gland you got it fixed.


Sent from my iPad using Tapatalk[/QUOTE

Hi Orange,

No worries and no need to say sorry. At the time I was looking for any ideas from anyone and appreciate your input. Having experienced a leaking front steering before, I was open to all ideas. Back in 2014 when I last replaced the steering cylinder seals the steering was acting up in both directions. (the fluid was leaking past the worn center seal when trying to turn both directions). The symptoms this time around were very odd and different.

At a minimum we all learned something about the steering controller to include where the OEM manufacturer is, a source for the parts manual and what the inside components look like etc. In my book while the troubleshooting was perplexing, it was worth it in the end and that's what the forum is about.

I'm just happy to have reliable steering again - in both directions. Thanks again
 

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Great write up Rob. Seems worthy of a Tech article.

re. that steering rod. I haven't had the umm pleasure of tackleing it yet but it's good to know it can take a lick'n.

Back when I ordered some parts for a repair I also ordered a set of those colored quick connect caps to replace my broken off ones. Kubota must have used a gorilla to torque those babys on cause I gave up and punted replacing them until necessary. Theres still enough of the colored collars to tell which connector goes where LOL.

Dave
 

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Discussion Starter #40
Great write up Rob. Seems worthy of a Tech article.

re. that steering rod. I haven't had the umm pleasure of tackleing it yet but it's good to know it can take a lick'n.

Back when I ordered some parts for a repair I also ordered a set of those colored quick connect caps to replace my broken off ones. Kubota must have used a gorilla to torque those babys on cause I gave up and punted replacing them until necessary. Theres still enough of the colored collars to tell which connector goes where LOL.

Dave

Dave,

Thanks for your support. Are you clairvoyant too? I put the FEL back on today and was thinking about replacing the quick connect caps too - 2 of the 4 caps on the FEL fittings are broken off (the fittings on the tractor). I've never messed with them before but if they are THAT tight, no sense messing with what is mainly cosmetic and ain't really broke.

This is off topic, but... Just came in from modifying my pair of Bxpanded FEL Forks. They have nice products but the steel where the attachment pins go through the top of the forks needs reinforcing. As delivered, they won't take much side stress as I found out the hard way.
Took some 2" long steel gas pipe, drilled it out so the the 1/2" fork attachment pins will go through the pipe and then drilled out the heads of each fork to fit in the pipe as bushings. Welding everything into place and did a little rough grinding on the outside faces so everything still fits. should be good to go now.

Now... time to work on upgrading the wing plow on my BX-23 - assuming we get anything to plow this year in DC.

Cheers, Rob
 
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