BH92 stabilizer leg valve control sticking

[eck1901]

L3540 with the L765 FEL and the BH92 backhoe connected through the remote hydraulic quick disconnect point on back. I plug in my hyd. lines and use a strap to keep the remote hyd. control next to the tractor seat pulled forward to send hyd. fluid back to the backhoe.

My hydraulic fluid is very clean, the filters (and presumably the fluid) changed only about 150 hours ago. I am meticulous in making sure quick connectors have been wiped clean prior to use. I even bought the boots for both ends of each connector and always use them when the backhoe is not installed.

I bought my tractor (1st time owner) about 2 years ago. The backhoe was a nearly new one added on by the dealer at my request. I never had any problem with the backhoe controls until after I reinstalled it after using my mower. That's when this showed up the 1st time.

After calling the dealer, they said to bleed the hyd. connectors by bumping both hoses several times until the pressure was gone. I did and it fixed it.

Several months later, after the 2nd time reinstalling after using the mower, the same thing has happened. Bumped and got it working again BUT noticed that one stabilizer leg control was still to move the handle to make the leg raise up. I worked it back and forth numerous times and it got better. I used the backhoe for several hours.

Now, after sitting 2 weeks, I have the same problem with the same stabilizer control. This is the only one that has ever given me problems. However, this time, after getting it to move fairly well, it was still stiff to move upwards (which pushes the valve downwards in the body), it did not get better. It immediately only got worse. This time the handle would not push as far as the other stabilizer leg control anytime during working the controls over. The control finally got where it would no longer let me push it towards the up direction.

The control will move the leg downward and the motion of moving it off center towards the down direction feels smooth and just like the other leg control. Only the up motion of the control will no longer budge off of center. The linkage appears fully intact, nothing missing or bent and the same as the other leg.

I took the control panel off the backhoe and identified the valve body as a Nabtesco 213256-01, N11 0065.

Help me on what to do next. I am way out from a dealer and would like to handle this myself. I'm a fairly good mechanic.

Also, please advise where I might get a repair manual on the backhoe.

Any help is appreciated.

Thanks.

 

[100 td]

Have a look for your backhoe here, full parts diagrams should help you pulling the spool and assessing what is wrong with it.
http://www.kubota.com/part/partsList.aspx
Also are you saying the hoe is plumbed through the remote valves on your tractor which you need to have the valve held open for the hoe to work?
http://198.144.16.129/WSM--BH92_p_71305.html

 

[scdeerslayer]

That is not how the backhoe hydraulics should be hooked up, unless there is something different with your tractor. There is supposed to be a loop on the back of the tractor. You break the loop and install the backhoe inline, then when you disconnect the backhoe, you close the loop. Your rear remotes should not come into play.

 

[eck1901]

Yes, my unit uses the remote hyd. The dealer used this since the remote was available and it would not require adding the loop hose. There is no issue regarding this part - the backhoe has worked successfully for probably 50 hours or so.

 

[eck1901]

Thanks for that link. I have used the Kubota parts diagram to see/match up my photos and it is obviously very helpful.

 

[eck1901]

The service mgr. at the local dealer told me to:
1. Try spraying penetrating oil on the valve where the plunger goes into the body. I'll give it a try.
2. The spring on the bottom may be damaged and that part can be replaced.
3. Remove the top 2 screws and pull the spool out to inspect for trash and damage.

Other ideas or likelyhoods?

In looking at the diagram, I get the idea that the spool must be removed from the bottom. Anyone know which is correct?

 

[eck1901]

Just wanted to update that I fixed the problem.

The bottom side of the valve, where their is a spring that causes the valve to center (i.e. - no action), has an o-ring and a "keeper", or as they call it, a "wiper" to hold the o-ring in place. The top side of the valve has the same parts.

Well, when disassembled, the wiper and the o-ring on the bottom had been pinched and damaged. I suspect it was done at the factory. I bought the parts from the the dealer (o ring # 04816-00120 and wiper # RB401-70510). The o-ring was stock @ $2 and the other had to be ordered for $34.74 + tax + $7.50 freight. I got a 2nd o-ring to replace the top one since that would be protocol when opening up a valve.

The replacing the o-ring and wiper was easy - it must be done on the work bench! BUT - the real work was carefully marking each of 14 hyd. lines w/ duct tape and some tie wraps since the hyd. oil washed any permanent marker markings right off and made some of the colored tape fall off as well.

Then, remove the lines and pull the heavy backing plate and valve assy. off.

You MUST completely clean this thing up BEFORE removing the lines and add a bit more cleaning once on the bench. One spec of dirt could wreck your work.

Simply remove the top and bottom screws holding down the caps on top and bottom of the valve and unbolt the spring and pull the spool out. Inspect for any damage and scratches on the spool - mine was perfect.

Reinstall in reverse order. Works like a charm now.

 

[eck1901]

Photos attached.

 

[geoff]

That's was an interesting one, and so considerate to take time and post your solution, thank you.

 

[mendoAu]

I have a similar Kubota, a 3130. And I had a similar issue with a wiper valve seal. Wipers are kinda pricey for no more than they are. What I found was amazing was that if you put a wiper on the shaft and slightly "tip" it with your fingers it will "lock" the shaft from moving up and down or at least impede the movement of whichever valve you are using. Such a little piece can stop a big 'ol hydraolic backhoe from working correctly.......