Dan - would love that. I'm here to learn as well as to ultimately (hopefully...) diagnose and fix. I gathered the couple of parts to build the ag fitting pressure tester I mentioned in my first post by the same means - I saw a few posts here where people were using the same setup to diagnose their hydraulic system issues, and one gent posted the specific fittings he used. Communities like this one are gold and I appreciate the help.
M7060 - Sudden & complete loss of loader/3pt/remote hydraulics, but PS and Transmission still function?
- Thread starter jjb01016
- Start date
Would you like ms to put one rigether for you? I have the major pieces on hand and can do it cheaper than you can source them.
Dan
Knowing how to pressure test the hydro system would be good to know.
If anyone has time, I would love to see a list of what parts are needed and a procedure to do this type of test. A video would be great!
If anyone has time, I would love to see a list of what parts are needed and a procedure to do this type of test. A video would be great!
Alright - an update...looking for some more input from those with more knowledge base than I.
Dan / @TheOldHokie was kind enough to build me an inline pressure/flow test rig - basically a flow control valve and pressure gauge on a block and tee fitting. Thanks Dan!
I hooked up the test rig in-line to my "P" line coming from the pump, into the loader control valve. So basically the circuit is "P" line --> pressure gauge --> Flow Control Valve --> Outlet line back to "P" port on loader control valve. I opened the valve fully and started up the tractor and set the RPMS to ~2000.
With the flow control valve full open, I was getting 0 PSI on the gauge. As I closed the valve, no increase in pressure was noted - the needle never departed 0 PSI. This held for all the way to almost full close of the valve. Based on feedback from Dan, I should have seen pressure increase as I closed the valve.
I shut the tractor off, then pulled the "P" line off the test rig and dumped it straight into a clear plastic jug. Started the tractor up, and all I was getting for flow off the line was a continuous trickle, both at idle and at 2000-ish RPM. I kept the tractor running for about 30 seconds, no change. This would be like the same trickle if you just bumped your faucet past the drip drip drip stage.
Curiously, when I shut off the tractor, I did get a big, short gush of hydraulic fluid out the line into the jug, just before the engine fully stopped running (but only after cutting the ignition via the key).
I think I can say obviously that I'm not getting any pressure into the loader control valve. And that I'm not getting any notable flow, either. And I think the big "gush" I noted when turning the tractor off means I don't have a block in the circuit. I think this also tells me it's not a stuck relief valve in the loader control valve, since the above testing is functionally before that relief valve.
So what other checks should I make? Or is the problem already apparent based on the above? Is there another relief valve in the circuit ahead of the loader control valve?
Dan / @TheOldHokie was kind enough to build me an inline pressure/flow test rig - basically a flow control valve and pressure gauge on a block and tee fitting. Thanks Dan!
I hooked up the test rig in-line to my "P" line coming from the pump, into the loader control valve. So basically the circuit is "P" line --> pressure gauge --> Flow Control Valve --> Outlet line back to "P" port on loader control valve. I opened the valve fully and started up the tractor and set the RPMS to ~2000.
With the flow control valve full open, I was getting 0 PSI on the gauge. As I closed the valve, no increase in pressure was noted - the needle never departed 0 PSI. This held for all the way to almost full close of the valve. Based on feedback from Dan, I should have seen pressure increase as I closed the valve.
I shut the tractor off, then pulled the "P" line off the test rig and dumped it straight into a clear plastic jug. Started the tractor up, and all I was getting for flow off the line was a continuous trickle, both at idle and at 2000-ish RPM. I kept the tractor running for about 30 seconds, no change. This would be like the same trickle if you just bumped your faucet past the drip drip drip stage.
Curiously, when I shut off the tractor, I did get a big, short gush of hydraulic fluid out the line into the jug, just before the engine fully stopped running (but only after cutting the ignition via the key).
I think I can say obviously that I'm not getting any pressure into the loader control valve. And that I'm not getting any notable flow, either. And I think the big "gush" I noted when turning the tractor off means I don't have a block in the circuit. I think this also tells me it's not a stuck relief valve in the loader control valve, since the above testing is functionally before that relief valve.
So what other checks should I make? Or is the problem already apparent based on the above? Is there another relief valve in the circuit ahead of the loader control valve?
I have looked at the hydraulic schematic for the M9950 and the reluef is in ths rear just ahead of the aux remotes. Show us where your loader is connected into the tractor hydraulic system.
I have the OEM Kubota LA1154 3rd function kit, so my lines should follow the below schematic. I highlighted the route from the pump (I think!).
Does that 3rd Function Valve body have its own relief ahead of the loader control valve???? Or some other bypass? Could something there have failed? I think I'm going to go setup the test rig on the pump line heading in to the 3rd function valve body and see what I get....I'll report back.
Does that 3rd Function Valve body have its own relief ahead of the loader control valve???? Or some other bypass? Could something there have failed? I think I'm going to go setup the test rig on the pump line heading in to the 3rd function valve body and see what I get....I'll report back.
Interesting wrinkle. The third function valve is ahead of the loader valve. So when testing at the loader valve you still have the 3rd function between the gauge and pump. And yes the third function has an inlet pressure relief in it.
I see two possibile failure modes for this sudden failure:
- The rekief in the third function is stuck open
- The third function valve is stuck in a shifted position
Dan
Last edited:
IT'S NOT THE PUMP!!! WOOHOO!!!
I disconnected the line from the pump to the 3rd function valve and dumped it straight into a plastic jug, since I didn't have the proper fittings to hook up my test rig to it (why can't they just use one common size!?).
As soon as I started the tractor, fluid gushed from the hose. YES!
OK, so the problem is DEFINITELY in the 3rd function valve.
What can I do to test for the above two conditions you mention Dan?
I disconnected the line from the pump to the 3rd function valve and dumped it straight into a plastic jug, since I didn't have the proper fittings to hook up my test rig to it (why can't they just use one common size!?).
As soon as I started the tractor, fluid gushed from the hose. YES!
OK, so the problem is DEFINITELY in the 3rd function valve.
What can I do to test for the above two conditions you mention Dan?
Now you see why I was reluctant to condemn the pump after your first test.
At this point you are down fo inspection of the third function. Unplug the electrical connections and see if that does anything.
Ok - found out the culprit - not sure exactly what functionally is happening yet. But when I unplug this connector from the 3rd function valve, viola - hydraulics are fully functional again. I'll look through the manual in a minute but figured I'd get this posted up first.
EDIT: Ok, so it's the rear Solenoid Valve harness, # 1 below, that's causing the issue. So what exactly is happening and why would this be sticking "ON" and causing the loss of hydraulics?
EDIT: Ok, so it's the rear Solenoid Valve harness, # 1 below, that's causing the issue. So what exactly is happening and why would this be sticking "ON" and causing the loss of hydraulics?
Last edited:
You have a short in the wiring or one of the third function buttons is stuck. That e mm ergiizes the valve which in turn blocks the neutral circuit. A fairly common failure.
Dan
Just realized something in hindsight that may help others who read this and have a similar issue. I noted in an earlier post the following:
Good to know.
So what was happening here is that when I keyed the tractor OFF, electricity acted faster to change the state of the solenoid valve than the hydraulic fluid and the pump gearing could slow down. Key gets shut off, electricity stops flowing to the solenoid valve, it changes state - but the pump is still rotating enough via the engine to continue to momentarily pump fluid. So, it gets routed to the previously not-flowing circuit - hence the big sudden gush as the tractor was shutting down.
Good to know.
More importantantly understand the circuit you are trying to diagnose.
The late coming discovery that the third function valve was ahead of the loader is what solved this. As soon as that was revealed the problem was quickly located.
Dan
Yep, agreed as well. I appreciate all the help tracking this down. The bigger hurdle for someone new to the hydraulic system is probably familiarization, versus troubleshooting the particular failure point and mode. I'm going to add a bit more around this point to your hydraulics basics thread.