New BX25D hydraulics quit

[pcartland]

The dealer replicated the problem today. The service manager disconnected the backhoe and it resolved the loader issue. He now suspects it is the valve block on the loader. He's waiting for permission from Kubota to tear it apart.

 

[onyamatey]

I am a mechanic at a Kubota dealer in Australia, I actually assembled a BX25 out of the crate today and guess what......... The usual seat latch in backhoe position doesn't lock in. We see it a lot, it's a misalignment problem where the locking rod that goes across the base of the ROPS is slightly in the wrong position which messes up the geometry of where the seat is latched on.
The service bulletin to 'supposedly' solve the problem is a crock of s#*$, it's about fitting a stronger spring kit to give it more force to latch it in harder and hopefully make it lock. The idea is ambitious, but the reality is a lot different. Kubota make a brilliant product, but their product support engineers aren't always the best at masking obvious faults.
What we do to correct this design/manufacture fault is use a die grinder to evenly take off a small amount of material on the seat base so it neatly follows the curvature when it contacts the locking rod, by doing this the seat base correctly fits snug onto the rod and the latch locks in effortlessly. Problem solved. And we don't even approach Kubota for warranty payment. It's a waste of time trying to get money from them because they refuse to accept their is a fault with their product....until people fall off their backhoe seats and are seriously injured or killed and the law suits roll in. That's when they take action haha

As for your hydraulic problem, I will check out the hydraulic schematic tomorrow at work and give you a better idea of possible causes.

 

[pcartland]

Thanks onyamatey. I talked to the dealer today and Kubota wants him to tear apart the hydraulic block on the backhoe. He doesn't think he'll be able to fix it so he's ordered a new one but it won't arrive until monday. That means I'll lose another weekend opportunity to prepare a dog run for my wife's new Newfoundland. We don't get that many nice weekends in Alaska so I'm pissed.

 

[pcartland]

Sorry onyamatey. I should have read closer. My latching problem isn't in the backhoe position. It's in the loader position. The service bulletin is for the backhoe position but that isn't where I'm having the problem. The dealer is ust doing it on the off chance that it might help.

 

[onyamatey]

Thanks onyamatey. I talked to the dealer today and Kubota wants him to tear apart the hydraulic block on the backhoe. He doesn't think he'll be able to fix it so he's ordered a new one but it won't arrive until monday. That means I'll lose another weekend opportunity to prepare a dog run for my wife's new Newfoundland. We don't get that many nice weekends in Alaska so I'm pissed.

Sorry I've been out all day in the field service truck working in the pouring rain so I didn't grab a chance to get onto the computer to check out the hydraulic flow of the backhoe valve. But from what you are saying where the loader completely stops working, that indicates the normally open center of the backhoe valve is closed and preventing return oil from the loader to travel back to tank via the power beyond circuit through the backhoe valve, this creates a hydraulic lock on your loader.
The backhoe valve really is quite simple inside, just a heap of spools and I can't say I've ever seen one fail or leak, they are very reliable, it's very un-Kubota'ish for a valve to have problems. One thing I can suggest that I have seen more than a few times before is not the valve, but the hydraulic quick connect couplers between the tractor and the backhoe. Sometimes the plunger inside the end of the coupler can break or cock sideways causing it to slow or completely block the oil flow between tractor and implement. Might be worth a look or try a different set of couplers from a donor tractor in the dealers yard ?

 

[EE_Bota]

One thing I can suggest that I have seen more than a few times before is not the valve, but the hydraulic quick connect couplers between the tractor and the backhoe. Sometimes the plunger inside the end of the coupler can break or cock sideways causing it to slow or completely block the oil flow between tractor and implement. Might be worth a look or try a different set of couplers from a donor tractor in the dealers yard ?

I had this happen, and I posted pictures here somewhere of the rubber from the poppet seats getting extruded.
Spring imbalance combined with lack of physical stops to enforce position resulted in one poppet being way open and the other poppet being closed. Though new, they were not of the same quality that Kubota uses, but even the better brands can have a dud now and again.

 

[swelly]

Good Day everyone.

And good news, the customers unit is fixed and he will be able to finish the dog run.

I am the Service Manager at the dealership working on the customers tractor. I found a few problems with the unit after working on it myself yesterday and today.

First there was something in the backhoe control valve causing an issue with the spool for the bucket circuit. When taking the valve apart, The spool was had to move up and down w/the centering spring removed. When dis-assembled, I found no damage, or could I find what ever was causing the hang up. I took the rest of the valve apart, thoroughly cleaned and flushed it. Resealed and put back together, and on the bench all spools seemed to operate correctly.

Second issue arose after reinstalling the valve on the unit. At that point the bucket dump side of the spool would not return to center on its own. Upon inspection, I found the the bolt on the top of the control rod between then handle and spool to be to tight.

Next the seat latching issue,,, The issue was with ease of getting it latched in the normal position. Upon looking it over, I found the pins that the latch hooks on to be out of adjustment. After adjusting or straightening them, it works fine and just like the others in the yard. How they got bent, I do not have a clue. These units arrive assembled, and I see no indication of something landing on or hitting the unit. I can only speculate it happened in transit.

 

[RaydaKub]

Hey Swelly, :welcome: to TBN.

Glad to hear you could help the guy out. With you insight you could be really busy answering questions on this forum. We look forward to hearing from you in the future.

 

[swelly]

Hey Swelly, :welcome: to TBN.

Glad to hear you could help the guy out. With you insight you could be really busy answering questions on this forum. We look forward to hearing from you in the future.

Thanks,

I will try and chime in when possible. Have to admit that I only knew the customer had posted because he sent me an email with some of the responses. By far I do not consider myself an expert, but will help out whenever I can.

This unit is not the Kubota norm by any means. If we had to stay busy fixing new stuff, we would starve. This valve, as someone mentioned before is a new monoblock, vs a stack on the previous BX25's. Wish I could of found what was hanging up the spool, but given the tight tolorences, it could be something very small.

Good thing is the customer appears to be fixed, and I am scheduling the deliver back to his house.

 

[radioman]

sounds like a happy ending!

Question - what the difference between a monoblock and stack valve?