Backhoe boom power loss

[rScotty]

I can’t even get it up enough to unseat the “keeper”, which secures it in the up position when not in use.
Hmmm, I’ll try switching hoses, sounds easy and logical to me.

I like that idea!! Clever idea, and it ought to work. Switch hoses and see if you can get the boom to work while some other function - like bucket curl - becomes a problem. If so, then the problem is in the control valve not cylinder.

 

[mattphillips18]

It is the valve! Not the cylinder! Smart folks on this forum. I put the suspect valve on the hoses controlling, for lack of knowing the name, the forearm and it just rose up without any input. I could bring it down slowly, but as soon as I released pressure, it floated up. So that valve is shot. The boom was hooked up to the functioning valve and was good as new.
Anybody replace these valves before?
And thanks, again for the great ideas and confidence boosters.

 

[mattphillips18]

I would suggest checking the control valve assembly as well. I had a similar sounding situation on a fairly new Kubota. Took all the weight off the affected cylinder, removed the hose from the control valve, bled a little fluid out, and reinstalled the hose. Must have had a piece of something in there that came out as I haven't had it happen again. You could also switch it around with another hose at the control valve and see if it works off a different port. If so, then it's not the cylinder.

I’m curious if I were to just take off the hoses from this valve and pump fluid out if maybe a stuck piece of crud was the problem? Though the problem wasn’t necessarily a sudden onset, it got progressively worse over time using it, if I had to guess 30 minutes of actual use? It could have come to me with an issue and I didn’t recognize it, only to have it degrade quickly.

 

[rScotty]

Last year several of the Kubota M59 owners worked through a similar problem. Search on "M59 backhoe" & see if anything comes up. I'll do the same and see if I find it. Maybe smokeydog remembers...

The short story is that we found out that any BH control valve assembly or even single replacement relief valves are mega-expensive to replace. But they turned out to be easier than anyone was expecting to clean and make work like new. The trick was to figure out exactly which relief valve was the culprit and then simply take it apart and clean the valve mating surfaces. Sometimes no crud was found and it still worked better for the attention.

Taking a relief or check valve apart does take patience and is much helped by havng a good set of factory shop and parts manuals.
Good Luck,
rScotty

 

[rScotty]

I’m curious if I were to just take off the hoses from this valve and pump fluid out if maybe a stuck piece of crud was the problem? Though the problem wasn’t necessarily a sudden onset, it got progressively worse over time using it, if I had to guess 30 minutes of actual use? It could have come to me with an issue and I didn’t recognize it, only to have it degrade quickly.

It's worth a try. I once got one of my BH control valves with what seemed to be a "crud-in-the-relief-valve" problem to working right again by lifting the boom manually and then working the lever rapidly as it fell under gravity. On about the third try it started working normally and has continued to work right for the next ten or more years.
rScotty

 

[gtunney]

I’m curious if I were to just take off the hoses from this valve and pump fluid out if maybe a stuck piece of crud was the problem? Though the problem wasn’t necessarily a sudden onset, it got progressively worse over time using it, if I had to guess 30 minutes of actual use? It could have come to me with an issue and I didn’t recognize it, only to have it degrade quickly.

There might well be a video out there on doing this. You can find videos for just about anything these days. By the way, welcome to the forum Matt! Be sure to update us on your final solution and stick around and don't be a stranger. No doubt at some point you'll be able pay back in the form of your own lesson learned. Cheers.

 

[mattphillips18]

View attachment IMG_0200.jpeg
On a whim I decided to unscrew the cap on this and wasn’t expecting the over pressure valve to be a part of the cap. Is this right? It rattles a bit in there, but I haven’t pulled too hard to get it out for fear that it’s supposed to be held on like this.

 

[mattphillips18]

Fixed. That valve had come unscrewed over time and was the issue. I was able to gently pop it out of the valve cover and screw it snugly into place with a bit of blue lock tight. Put the cover back on and it works better, smoother than since I’ve owned it. Which isn’t long.
Thanks again for the help in understanding these things and the ideas to try!