L4240 lost Hydraulic pressure and HST whining.

[RGibbs4240]

Its not working now and it seems something is blocking the power beyond circuit. I am not questioning your plumbing just trying to understand it so I can figure out where to poke next.

1. Third function is fed by PB from loader valve?
2. Third function then feeds remotes via a hose you installed?
3. Power beyond port on remotes goes back to tractor.
4. Tank return on remotes goes where?

Dan

The third function is piped under seat. I assume power beyond port and was installed by the dealer.

I purshased a kit that piped to the third function for rear remotes. It has a push pull knob the direct fuild to the front 3rd function or the rear remotes.

The front 3rd function and rear remotes would go back to the tank through the 3rd funtion.

I have disconnected all that was quick connect to the 3rd function. that basically brings PB up and a return hose.

Here is the rear remote kit.

Kubota Remote Hydraulic Kits | TractorInnovations

Tractor Innovations Remote Hydraulic Kits for Kubota Tractors. Custom ready to Plug & Play. Made in USA.

www.tractorinnovations.com

Thanks for your help.
Rich

 

[TheOldHokie]

The third function is piped under seat. I assume power beyond port and was installed by the dealer.

I purshased a kit that piped to the third function for rear remotes. It has a push pull knob the direct fuild to the front 3rd function or the rear remotes.

The front 3rd function and rear remotes would go back to the tank through the 3rd funtion.

I have disconnected all that was quick connect to the 3rd function. that basically brings PB up and a return hose.

Here is the rear remote kit.

Kubota Remote Hydraulic Kits | TractorInnovations

Tractor Innovations Remote Hydraulic Kits for Kubota Tractors. Custom ready to Plug & Play. Made in USA.

www.tractorinnovations.com

Thanks for your help.
Rich

OK - stop right there. You do not have a remote valve - you have the Tractor Innovations diverter bodge. That is a manual diverter valve on the bucket work ports of the loader valve. The diverter switches the bucket work ports between a set of rear remote outlets and the bucket cylinders. The remote outlets are controlled by the bucket spool on the loader valve when the bucket is disabled and vice-versa. None of that is in the power beyond circuit.

Returning to what we know or think we know,. What we believe is the the pump is deadheaded based on loss of hydraulic functions, heating, and engine loading. We also know that when you remove the lift cylinder rod end hose the loader lift circuit works. That means the oil is coming into the loader valve inlet properly where it is diverted to the work port for the lift cylinders causing the rod to extend forcing return oil out of the other end into the bucket. When that hose is reconnected the exhaust oil is blocked and the cylinders cannot extend and the loader does not work. That means the lift cylinder oil cannot get to tank via the power beyond outlet on thr loader valve - e.g. the power beyond circuit exiting the loader valve is blocked by something down stream of it. At this point I can only come up with two possibilities:

1. The third function valve if it is installed after rather than before the loader valve.
2. The 3pt valve and cylinder - i.e. the infamous feedback linkage.

I am running out of places that are easy access to test. Where is the third function valve mounted and can you post a picture of it?

Dan

 

[RGibbs4240]

OK - stop right there. You do not have a remote valve - you have the Tractor Innovations diverter bodge. That is a manual diverter valve on the bucket work ports of the loader valve. The diverter switches the bucket work ports between a set of rear remote outlets and the bucket cylinders. The remote outlets are controlled by the bucket spool on the loader valve when the bucket is disabled and vice-versa. None of that is in the power beyond circuit.

Returning to what we know or think we know,. What we believe is the the pump is deadheaded based on loss of hydraulic functions, heating, and engine loading. We also know that when you remove the lift cylinder rod end hose the loader lift circuit works. That means the oil is coming into the loader valve inlet properly where it is diverted to the work port for the lift cylinders causing the rod to extend forcing return oil out of the other end into the bucket. When that hose is reconnected the exhaust oil is blocked and the cylinders cannot extend and the loader does not work. That means the lift cylinder oil cannot get to tank via the power beyond outlet on thr loader valve - e.g. the power beyond circuit exiting the loader valve is blocked by something down stream of it. At this point I can only come up with two possibilities:

1. The third function valve if it is installed after rather than before the loader valve.
2. The 3pt valve and cylinder - i.e. the infamous feedback linkage.

I am running out of places that are easy access to test. Where is the third function valve mounted and can you post a picture of it?

Dan

I will try to get a picture tomorrow. It is installed right above the quick connects for the loader, on a bracket.

The plumbing goes to the rear, not like the ones I have seen on the 3901's.

FYI, I had innovations diverter plumb mine to the 3rd function, not to the loader.

Can I jump the the couplings on the 3rd function to bypass any thing?

How do you trouble shot the 3pt valve and cylinder - i.e. the infamous feedback. That is were the mouse nest was.

 

[TheOldHokie]

I will try to get a picture tomorrow. It is installed right above the quick connects for the loader, on a bracket.

The plumbing goes to the rear, not like the ones I have seen on the 3901's.

FYI, I had innovations diverter plumb mine to the 3rd function, not to the loader.

Can I jump the the couplings on the 3rd function to bypass any thing?

How do you trouble shot the 3pt valve and cylinder - i.e. the infamous feedback. That is were the mouse nest was.

The diverter is not the problem.

Mouse nest in feedback linkage might be. Mske sure its free to move.

Dan

 

[North Idaho Wolfman]

It's an issue with the three point feed back linkage being mal adjusted.

 

[Russell King]

On the three point lift and feed back mechanism…
When the arms are at their highest lift position it can go into over pressure and the relief valve will kick open. You would hear a squealing noise in that condition. There is a process to adjust it so it doesn’t go into bypass.
The feedback rod also provides the position control mechanism feedback to stop the lifting when the arms reach the set lift position basically putting the valve back into a neutral position.

Since you had a rat nest in the area, the urine may have rusted the feedback mechanism into a fixed position and then bent the rod. Inspect the feedback mechanism and see if you can move the tab that goes into the tractor or lower and then raise the three point arms and watch the feedback rod and the tabs to see what happens.

 

[RGibbs4240]

The diverter is not the problem.

Mouse nest in feedback linkage might be. Mske sure its free to move.

Dan

 

[RGibbs4240]

Here are the images of my setup. Got it fixed. The third function was stuck in a position, not in the middle. I had a hydraulic hose with a male and female quick coupler and jumpered over the two ports. Tractor and five after that.

 

[TheOldHokie]

Here are the images of my setup. Got it fixed. The third function was stuck in a position, not in the middle. I had a hydraulic hose with a male and female quick coupler and jumpered over the two ports. Tractor and five after that.

Ĥmm - I suspected something like that.

Did you jumber inlet and outlet or the two work ports? I would not expect couplers on the inlet/outlet.

Dan

 

[RGibbs4240]

Ĥmm - I suspected something like that.

Did you jumber inlet and outlet or the two work ports? I would not expect couplers on the inlet/outlet.

Dan

The two work ports.