HELP! My Backhoe won't swing left!

[rScotty]

I got a chance to play with this. I just swapped the swing hoses from their control valve onto the boom control valve and vice versa. The problem moved to the boom! I had no power for boom down!

So now the problem is isolated to the control valve or the actual pump? Steering seems fine, and I have power in 1 direction, so I'm assuming the pump and main relief is ok. So I think that means the actual control valve is the issue???
ac

Wow! It's always good to run more tests. And that one provided real results..... I'm very impressed.... and glad you didn't just go and pull the swing cylinder apart.

OK,,, some questions.
1. You first posted on this problem with an L45 back almost 7 years ago in 2013 after a friend had used your hoe. Is this the same L45?
2. Which way is "Left"? Facing forward left or in backhoe operator position?
3. Why would it not be control or relief valve? I believe there is a separate swing pump - but don't see how that could cause a problem in one direction only. Does the L45 have a separate steering pump, too?
4. Hmmm.....could it be a relief valve? We know people have had problems with relief valves in that circuit before. Is there any way? I need to look at the hydraulic schematic to determine that - more about hydraulic schematic reading below..

How about one more test.... just to confirm things? Is it necessary or reasonable?
If you swap hoses again, I'm thinking that the stabilizers are also 2 way cylinders with an easily defined right and left.

Re the hydraulic schematic. I've been doing a self-study on hydraulic schematics. Fluid Power World published an excellent series of tutorials beginning with simple circuits and progressing up through fairly complex systems. All free and online. Keyword is "Hydraulic Symbology" by Mary Gannon and Josh Cosford. On the Fluid Power World publication website.
I'll take a look at the Kubota Shop Manual tonight and see if I can get any insight into what you've learned by swapping hoses.

Luck,
rScotty

 

[Smokeydog]

Not good that you are having problems.

Good that you made a clever test that narrows down the problem components.

Similar problems with my M59.
Loss of left swing once.
Loss of down boom twice.
Two independent hydraulic systems.
Both fixed themselves in minutes after many cycling attempts. With the boom cylinder it would drop down under gravity like usual but no pressure to push down. It “felt” like I had flow but no pressure while pushing down. It wasn’t deadheaded.

I suspected a stuck relief valve? A slug of air from a seep leak that maybe suddenly jam the relief open?? Does each direction and function have a separate relief?

Does everyone having a similar problem have a hydraulic thumb?

I don’t have many hours on the backhoe and bought it used so uncertain of the history. Judging by condition it didn’t get used very much. 99% of the time it works beautifully.

Sorry, I’m limited on my hydraulic knowledge and hope someone with enough puzzle pieces can figure this out.

 

[Monster5601]

Similar problems with my M59.
Loss of down boom twice.
fixed themselves in minutes after many cycling attempts. With the boom cylinder it would drop down under gravity like usual but no pressure to push down. It “felt” like I had flow but no pressure while pushing down. It wasn’t deadheaded.

I suspected a stuck relief valve? A slug of air from a seep leak that maybe suddenly jam the relief open?? Does each direction and function have a separate relief?

Does everyone having a similar problem have a hydraulic thumb?

I just had the same issue with my boom (BH76), no downforce, not dead-headed, it was like this all winter. Fixed itself after several cycles and warmer weather. I have a thumb but it is not hydraulic. My backhoe has relief valves on the boom, dipper stick, and swing only. I sure would like to find the root cause for this.

 

[Smokeydog]

When the backhoe has lost a function and was cycling to try to restore I did sometimes try other functions like the bucket, boom and out riggers. Control would return as mysterious as it happened. Noted no particular combination of use of other functions to fix the problem.

The times the temporary loss of functions happen were after days of sitting in storage. Operating backhoe at near idle speed. Increasing engine speed after loss of function didn’t seem to help.

So far temporary loss of function has been a frustrating quirk. Don’t know what causes it or what fixes it. Not sure what operating techniques could prevent it.

Currently the backhoe is not on the tractor. Most work is in 3pt mode. While the backhoe mounting and dismounting is surprisingly easy The removal and replacement of the 3pt arms takes some grunt strength because of their weight.

 

[Ished]

Has anyone just pulled the pins on the swing cylinders and tried swinging the hoe side to side and see if both cylinders are moving or is just one moving and the others staying out. I'm going to try this tonight when I get home. Because I have this problem going on and I just had my valve body rebuilt new fluid and filters and everything worked before and after then all of a sudden nothing. I have noticed in the past the swing was much stronger I can tell you when it was working my right swing is more powerful then the left swing with it working. Tried everything except just pulling the pins and seeing what happens I may just end up with a cylinder shaft laying in the yard and it shoots out if it's broken like the other guys.

 

[rScotty]

Has anyone just pulled the pins on the swing cylinders and tried swinging the hoe side to side and see if both cylinders are moving or is just one moving and the others staying out. I'm going to try this tonight when I get home. Because I have this problem going on and I just had my valve body rebuilt new fluid and filters and everything worked before and after then all of a sudden nothing. I have noticed in the past the swing was much stronger I can tell you when it was working my right swing is more powerful then the left swing with it working. Tried everything except just pulling the pins and seeing what happens I may just end up with a cylinder shaft laying in the yard and it shoots out if it's broken like the other guys.

Hello Ished, I'm still here and still are most of the others who have posted. I've never had a repeat, but many have. So far as I know, only one person ever posted about this being a broken part in a cylinder.

Glad you are updating this old thread. Right now what we have is 8 years of evidence from lots of owners. It all seems to point to this temporary loss of function being just what Smokeydog says in post #54 - "a frustrating quirk".

That's not very satisfying explanation, though. I'd like to know more, so I hope you do plenty of experiments and post results.
Mine has never done it again (since 2013 I believe)....Power is good in both swing directions.
rScotty

 

[Smokeydog]

Has anyone just pulled the pins on the swing cylinders and tried swinging the hoe side to side and see if both cylinders are moving or is just one moving and the others staying out. I'm going to try this tonight when I get home. Because I have this problem going on and I just had my valve body rebuilt new fluid and filters and everything worked before and after then all of a sudden nothing. I have noticed in the past the swing was much stronger I can tell you when it was working my right swing is more powerful then the left swing with it working. Tried everything except just pulling the pins and seeing what happens I may just end up with a cylinder shaft laying in the yard and it shoots out if it's broken like the other guys.

Why was the valve body rebuilt? Because of the loss of control?
I have lost temporary control on two circuits, left swing and down boom. The down boom was odd as I had gravity down but no pressure down for a few minutes. Intermittent problems are the hardest to fix and repair.

I suspected air bubble in the system somehow stuck open a relief or anticavtation valve. I’ve studied hydraulic circuit diagrams without convulsive pinpoint of the problem.

Evidence to maybe support air is I had a slight leak at one of the tractor side QDs for the backhoe. Tighten and fixed after removing the backhoe. Since then had not had a problem for short two times I used the backhoe since. Only 50% certain that might have fixed the problem. Time will tell.

For either of the backhoes have not noticed a faster swing or power difference to either side.

 

[Ished]

No I rebuilt it because I was tired of it leaking really bad I have roughly 1300 hours on it and dont baby it. I was looking at the new jcb 1cxt because sometimes I just need more power and not a bigger machine.

But I went out pressure washed everything and inspected it all and cant find a leak now and cylinders looked good and guess what after I reconnected the hoe everything was working again. I'm only guessing that their maybe was air trapped that wouldnt get out only till it was worked hard. Im still not happy with this thought but I'm going to keep everyone updated

 

[Ished]

Just wanted to update everyone I fixed my swing problem. I ended up swapping top to bottom bottom to top on the valves not the hose. My swing problem changed with the swap. So I looked to see how much a valve was to replace. Way to much money for something that has springs and an o ring so I took mine apart guessing the valve the followed with the problem was now the bottom valve. I was told by kubota it was un serviceable, they are right to extent. There's an o ring and backer ring that sits inside a cup that holds a needle in place. Low and behold a small piece of oring that has been rolled off by the backer ring pinching the o ring. Took to local shop for o ring sizing they were surprised how loose fitting the oring was on the valve. They suspect when the unit is cold the o ring rolls on it self inside and cause a poor seal causing the no swing. Sometimes with the split style backer ring the o ring pinches and well my tore but it worked sometime and sometimes didn't. So I replaced the oring a very loose fit but put it back together and power left and right more then I ever had for pushing the machine side to side. Now I just to rebuild my boom cylinder never ends. But if anyone wants pictures or what I did further feel free to take stuff apart it's only money if you break what's already broken

 

[rScotty]

Just wanted to update everyone I fixed my swing problem. I ended up swapping top to bottom bottom to top on the valves not the hose. My swing problem changed with the swap. So I looked to see how much a valve was to replace. Way to much money for something that has springs and an o ring so I took mine apart guessing the valve the followed with the problem was now the bottom valve. I was told by kubota it was un serviceable, they are right to extent. There's an o ring and backer ring that sits inside a cup that holds a needle in place. Low and behold a small piece of oring that has been rolled off by the backer ring pinching the o ring. Took to local shop for o ring sizing they were surprised how loose fitting the oring was on the valve. They suspect when the unit is cold the o ring rolls on it self inside and cause a poor seal causing the no swing. Sometimes with the split style backer ring the o ring pinches and well my tore but it worked sometime and sometimes didn't. So I replaced the oring a very loose fit but put it back together and power left and right more then I ever had for pushing the machine side to side. Now I just to rebuild my boom cylinder never ends. But if anyone wants pictures or what I did further feel free to take stuff apart it's only money if you break what's already broken

Congrats on taking it apart and doing it yourself. And maybe you have solved the mystery.

It seems like a piece of O ring holding an overload relief valve from closing would eplain all the things we have seen so far, including having unequal swing power in both directions.

I do wonder about tha oversize O ring you found. It seems odd. There are some fluids that will cause O rings to expand. It might be worth tapping off some of the trans/hydraulic fluid in your machine and putting it in a jar with some O rings just to check.
To see what can happen, coat some standard hardware store O rings with vaseline and put them into a zip lock. Compare with a new one in a few months. Amazing.

Here is a scan of an M59 control valve stack. It seems similar to your L45 valve. Can you point to which O ring that you replaced? Is the split backer ring shown?
Thanks, rScotty