B21 complete loss of hydraulic function

[B21GeaugaOH]

Hi all, just found this wonderful site! FAR more information than Kubota’s site. Four days ago I was moving 8 sheets of plywood on the forks of the front end loader, dealer forks. The plywood went from vertical to horizontal as I hit a bump, bounced me and the machine kinda hard…. After that point I’ve had no hydraulic function in the front end or the backhoe. What I’ve checked: hydraulic fluid level is fine, NO visible signs of leaks anywhere/parked on concrete, no loss wires, bent or disconnected hoses, tractor starts and runs fine, 3 point/ backhoe selector in proper position and seems functional, PTO works, power steering does not work, tractor drives around fine and respondes to RPMs…. Am I missing something to double check? What is an indication of hydraulic pump failure? Is there a separation of transmission and hydraulic functions that I don’t understand? I changed all my fluids and filters this past January and the machine has been fine, until now. Also, I’m the original owner and she’s been well taken care of… thank you in advance to any and all who may be able to give me guidance. JT

 

[Russell King]

If the three point hitch is still working then your pump is fine (working being defined as lifting a heavy implement not just moving the arms up).

I would check the hose connections at the loader valve. Remove any quick disconnect and reattach it to the valve. Start with the hose that connects into the Power in port (P) from the tractor pump or block.

 

[TheOldHokie]

Hi all, just found this wonderful site! FAR more information than Kubota’s site. Four days ago I was moving 8 sheets of plywood on the forks of the front end loader, dealer forks. The plywood went from vertical to horizontal as I hit a bump, bounced me and the machine kinda hard…. After that point I’ve had no hydraulic function in the front end or the backhoe. What I’ve checked: hydraulic fluid level is fine, NO visible signs of leaks anywhere/parked on concrete, no loss wires, bent or disconnected hoses, tractor starts and runs fine, 3 point/ backhoe selector in proper position and seems functional, PTO works, power steering does not work, tractor drives around fine and respondes to RPMs…. Am I missing something to double check? What is an indication of hydraulic pump failure? Is there a separation of transmission and hydraulic functions that I don’t understand? I changed all my fluids and filters this past January and the machine has been fine, until now. Also, I’m the original owner and she’s been well taken care of… thank you in advance to any and all who may be able to give me guidance. JT

If PS and implement hydraulics are both dead I am thinking you have a pump problem of some sort.. First order of business is check for flow out of the pumps.

Dan

 

[Mountainman]

B21 there are separate pumps for driving and other hydraulic functions. The hydrostat is a pump/motor that drives the tractor and has a charge pump on the front to help keep oil flowing to it. But i believe it also gets fluid from the hydraulic pump after the power steering. So i wouldn't drive it until you figure it out. But like @TheOldHokie said you need to figure out if the hydraulic pump is putting anything out. There is a priority valve on top of the pump as well

 

[Russell King]

Reading your first post again I see that you have a backhoe on it so I doubt you will be able to test the three point hitch to verify the pump is working.

You will have to figure out which hose comes from the pump to the loader valve P port (Power in).

To verify flow you can just remove that hose from the valve and put it into a clean 5 gallon bucket (tied into place) or back to the transmission fill port if it can reach. Tie or hold it in place just so it doesn’t make a mess if it moves. Start tractor and let run a few seconds in the bucket or as long as you care to if fed back to the transmission.

The pump has a good flow rate so don’t let it pump all the oil out of the case into the bucket (that can’t hold it all) and onto the floor, if you go the bucket route. If you have good flow into the bucket you can return the fluid to the transmission fill port.

If you have flow then check for pressure. You will need a gauge that is good for 3000 PSI and some fittings to connect to the hose. @TheOldHokie can provide instructions for that if you ask him.

 

[North Idaho Wolfman]

Its very possible a quick disconnect has come loose.
Disconnect and reconnect them all, including the BH loop and connection.

 

[Runs With Scissors]

I had a similar problem recently.

I immediately shut it down and after a visual inspection, I found one of the backhoe lines looked a little "Kaddi-wampus"

I found that a stick or something had popped off one of my backhoe lines so that it was still connected but looked "funny".

I "disconnected and re-connected" both lines and it was fixed.

I hope yours is that simple.

 

[TheOldHokie]

I had a similar problem recently.

I immediately shut it down and after a visual inspection, I found one of the backhoe lines looked a little "Kaddi-wampus"

I found that a stick or something had popped off one of my backhoe lines so that it was still connected but looked "funny".

I "disconnected and re-connected" both lines and it was fixed.

I hope yours is that simple.

I am going out on what I think is a pretty stout limb and guessing you did not lose PS in that event. AFAIK there are no quick couplers in the steering circuit on any Kubota tractor

 

[Runs With Scissors]

I am going out on what I think is a pretty stout limb and guessing you did not lose PS in that event. AFAIK there are no quick couplers in the steering circuit on any Kubota tractor

I believe you.

I can't remember the particulars of which circuits were doing what.

It was very unsettling to lose my hydraulics, so I just hit the panic button and "shut'er down" as fast as I could fearing that something big/expensive just broke.

I was relieved to find the problem with a visual inspection though.

 

[TheOldHokie]

I believe you.

I can't remember the particulars of which circuits were doing what.

It was very unsettling to lose my hydraulics, so I just hit the panic button and "shut'er down" as fast as I could fearing that something big/expensive just broke.

I was relieved to find the problem with a visual inspection though.

Thw problem I am having is understanding the PO's description.

For example how do the forks suddenly change position? Ehile transporting that is a closed work circuit and unless he/she operated the joystick isolated from the rest of the system.

To much confusion in the failure description to allow any reliable analysis. Thats why I suggested checking something simple fundamental, and easily verified.

Dan

 

[Russell King]

Thw problem I am having is understanding the PO's description.

For example how do the forks suddenly change position? Ehile transporting that is a closed work circuit and unless he/she operated the joystick isolated from the rest of the system.

To much confusion in the failure description to allow any reliable analysis. Thats why I suggested checking something simple fundamental, and easily verified.

Dan

As I understand what the OP meant, the plywood was in a vertical position (on edge) [and not well restrained]. The movement of the tractor jostled the plywood and it fell from vertical to horizontal position on the forks and that shifting load was enough to cause a jolt to the tractor.

My guess is that the plywood may have jerked one of the hoses during the fall.

 

[TheOldHokie]

As I understand what the PO meant, the plywood was in a vertical position (on edge) [and not well restrained]. The movement of the tractor jostled the plywood and it fell from vertical to horizontal position on the forks and that shifting load was enough to cause a jolt to the tractor.

My guess is that the plywood may have jerked one of the hoses during the fall.

Thanks for the plywood explanation - thats a lot clearer but does not help me out much.

What hose or hoses took out all of the hydraulic functions?

Dan

 

[B21GeaugaOH]

Thank you all for your input! Got back in town from work and had some time to look into the B21 some today. What I was able to do this far: disconnected and reconnected the quick connects- only 2, go to the backhoe, also connected them to themselves bypassing the hoe, nothing changed. Cracked various hardline fittings on the loader, machine running, no hyd fluid came out. Cracked couple of bolts on pump/ valve, machine running, no fluid. Found my service manuals with ancient pictures, in troubleshooting it lists as possible issues: control valve broken/ relief spring damage/ piston O ring or cyli damage/ suction pipe issues and lastly pump itself. Any thoughts out there ? I have another week out of town with my manuals and an iPad . Also if I need a pump I see that Orem is twice the price of other replacements… get what you pay for probs? Attached a pic of nuts that I cracked.

 

[TheOldHokie]

Thank you all for your input! Got back in town from work and had some time to look into the B21 some today. What I was able to do this far: disconnected and reconnected the quick connects- only 2, go to the backhoe, also connected them to themselves bypassing the hoe, nothing changed. Cracked various hardline fittings on the loader, machine running, no hyd fluid came out. Cracked couple of bolts on pump/ valve, machine running, no fluid. Found my service manuals with ancient pictures, in troubleshooting it lists as possible issues: control valve broken/ relief spring damage/ piston O ring or cyli damage/ suction pipe issues and lastly pump itself. Any thoughts out there ? I have another week out of town with my manuals and an iPad . Also if I need a pump I see that Orem is twice the price of other replacements… get what you pay for probs? Attached a pic of nuts that I cracked.

AnUnfortunately theres not much info available online for that tractor and the parts diagrams are not informative. The system is clearly different than the ones used on other models. The picture is the pump but what exactly the line is is not obvious. The other nut looks like it may be part ofxa pressure relief or flow divider. What manuals do you have and can you share? A hydraulic circuit diagram would be a goodcstarting point.

D

 

[B21GeaugaOH]

 

[B21GeaugaOH]

Looks like it’s study time for these diagrams. Anyone have knowledge that lends a possible failure point?

 

[TheOldHokie]

Looks like it’s study time for these diagrams. Anyone have knowledge that lends a possible failure point?

I popped for a $10 download of the WSM. I only had time for a quick glance on this crappy phone but it looks pretty simple. The pump output is split into PS and implement circuits by the flow divider mounted on top of the pump. Check for inlet oil at the loader valve or the loader supply port on the hydraulic outlet block.. I am guessing there is none.

Dan

 

[TheOldHokie]

Thank you all for your input! Got back in town from work and had some time to look into the B21 some today. What I was able to do this far: disconnected and reconnected the quick connects- only 2, go to the backhoe, also connected them to themselves bypassing the hoe, nothing changed. Cracked various hardline fittings on the loader, machine running, no hyd fluid came out. Cracked couple of bolts on pump/ valve, machine running, no fluid. Found my service manuals with ancient pictures, in troubleshooting it lists as possible issues: control valve broken/ relief spring damage/ piston O ring or cyli damage/ suction pipe issues and lastly pump itself. Any thoughts out there ? I have another week out of town with my manuals and an iPad . Also if I need a pump I see that Orem is twice the price of other replacements… get what you pay for probs? Attached a pic of nuts that I cracked. View attachment 141213

The leftmost fitting circled in red is priority flow going to your PS. Should be oil there with the engine running. A closer look at the pump has me wondering. Is that green area I circled a gap between the pump mounting flange and the engine block? That does not seem right to me.

 

[B21GeaugaOH]

!!! WOW I see what you mean. It’s hard getting on this with work travel!

 

[TheOldHokie]

!!! WOW I see what you mean. It’s hard getting on this with work travel!

Yes - i would expect the full length of that flange to be pulled up tight to the engine block. Looks like the pump may have pulled away and possibly lost engagement with the drive gear. If so that would account for a total loss of hydraulic flow.

Dan