L5450 hydraulic problem

[OliG]

Hello,

We have put the L5450 to its pace in forestry work since I got it last year and its been doiing a great job for us. We basically use it to collect and haul logs with a forwarding trailer. The trailer have its own hydraulic controls and is connected to one of the rear remotes. So to get hydraulic flow to the trailer, we basically jammed the remote in the forward position to activate it. In this position, the motor does not bog down like when the pump is under load and the FEL works normally so we assume the flow goes through the trailer without restriction.

We recently disconnected the trailer and hydraulics to do loader work, but realised that when unplugging the trailer hydraulic, the FEL becomes very slow, as if hydraulic power was used elsewhere. When plugging back the trailer hydraulics, Loader resume to works correctly...

My assumption is that the remote spool valve is not going back to center position correctly and is still trying to send partial flow to the quick connect, causing the loss of power to the loader. I tried to activate the remote in both positions and then to center but the problem is still there when no trailer connected. I guess that the stuck remote in the activated position for a long time is the cause of this...

Is my assumption correct? What else could cause the problem if not the remote valve itself? I was thinking to start by replacing the rear spring (040 in 2nd diagram) that seems to put back the spool in center position, does it makes sense?

Thanks a lot helping me fixing this.

Here are the parts diagrams :

 

[TheOldHokie]

Hello,

We have put the L5450 to its pace in forestry work since I got it last year and its been doiing a great job for us. We basically use it to collect and haul logs with a forwarding trailer. The trailer have its own hydraulic controls and is connected to one of the rear remotes. So to get hydraulic flow to the trailer, we basically jammed the remote in the forward position to activate it. In this position, the motor does not bog down like when the pump is under load and the FEL works normally so we assume the flow goes through the trailer without restriction.

We recently disconnected the trailer and hydraulics to do loader work, but realised that when unplugging the trailer hydraulic, the FEL becomes very slow, as if hydraulic power was used elsewhere. When plugging back the trailer hydraulics, Loader resume to works correctly...

My assumption is that the remote spool valve is not going back to center position correctly and is still trying to send partial flow to the quick connect, causing the loss of power to the loader. I tried to activate the remote in both positions and then to center but the problem is still there when no trailer connected. I guess that the stuck remote in the activated position for a long time is the cause of this...

Is my assumption correct? What else could cause the problem if not the remote valve itself? I was thinking to start by replacing the rear spring (040 in 2nd diagram) that seems to put back the spool in center position, does it makes sense?

Thanks a lot helping me fixing this.

Here are the parts diagrams :

I think you are on the right track but let me first describe how this circuit works:

1. Presumably this is an LA1150 loader but it really does not matter. The loader circuit comes off the hydraulic outlet on the front of the tractor. Oil flow comes out the block, through the loader valve and returns to the block where it continues to the rear.

1. The flow retruned by the loader valve continues to the rear where there is another take off for the remote valves, Same setup - pressure out, pressure in, and tank return for the remotes.

When the loader valve is operated to raise or lower the boom oil travels out to the loader cylinders and exhaust oil from the cylinders is sent to the power beyond circuit going to the remotes. Normally it goes through the neutral circuit in the remote valves and on to tank. If the remote valve is not in neutral that oil goes to the work circuit on the remote valve. If that circuit is disconnected the flow is blocked and the loader stalls.

So yes - its likely the spool in your remote valve is hung up and blocking the loader operation. Fixing that is going to require removing the valve. Once you get that fixed I suggest you reconsider your use of the remote valve to feed the trailer valve. IMO that is a poor choice and probably contributed to the failure of the valve.

I suggest you replumb the loader valve to provide a new set of outlets for the trailer, This is the same way Kubota plumbs a back hoe circuit:

1. Remove and discard the power beyond return hose and pipe from the loader valve and hydraulic block.
2. Run a new hose from the power beyond port on the loader valve to the rear and put a female quick coupler on it. That outlet will feed the trailer.
3. Run a new hose form the return port on the hydraulic block to the rear and put a male quick coupler on it. That is the return line for your trailer valve.

When connecting or disconnecting the trailer the engine must be shut off. And when the trailer is disconnected loop the male and female couplers on the tractor side together. This maintians the power beyond circuit. I think you will find that works a lot better and will take some of the stress off that remote valve.

It looks like you also have to use that same loop back scheme at the hydraulic block when you remove the loader. If you think you will need to remove the loader you will need to put the appropriate quick couplers on the loader valve end of the power beyond feed to the trailer outlets.

Dan

 

[OliG]

I think you are on the right track but let me first describe how this circuit works:

1. Presumably this is an LA1150 loader but it really does not matter. The loader circuit comes off the hydraulic outlet on the front of the tractor. Oil flow comes out the block, through the loader valve and returns to the block where it continues to the rear.

View attachment 88719

1. The flow retruned by the loader valve continues to the rear where there is another take off for the remote valves, Same setup - pressure out, pressure in, and tank return for the remotes.

View attachment 88720


When the loader valve is operated to raise or lower the boom oil travels out to the loader cylinders and exhaust oil from the cylinders is sent to the power beyond circuit going to the remotes. Normally it goes through the neutral circuit in the remote valves and on to tank. If the remote valve is not in neutral that oil goes to the work circuit on the remote valve. If that circuit is disconnected the flow is blocked and the loader stalls.

So yes - its likely the spool in your remote valve is hung up and blocking the loader operation. Fixing that is going to require removing the valve. Once you get that fixed I suggest you reconsider your use of the remote valve to feed the trailer valve. IMO that is a poor choice and probably contributed to the failure of the valve.

I suggest you replumb the loader valve to provide a new set of outlets for the trailer, This is the same way Kubota plumbs a back hoe circuit:

1. Remove and discard the power beyond return hose and pipe from the loader valve and hydraulic block.
2. Run a new hose from the power beyond port on the loader valve to the rear and put a female quick coupler on it. That outlet will feed the trailer.
3. Run a new hose form the return port on the hydraulic block to the rear and put a male quick coupler on it. That is the return line for your trailer valve.

When connecting or disconnecting the trailer the engine must be shut off. And when the trailer is disconnected loop the male and female couplers on the tractor side together. This maintians the power beyond circuit. I think you will find that works a lot better and will take some of the stress off that remote valve.

It looks like you also have to use that same loop back scheme at the hydraulic block when you remove the loader. If you think you will need to remove the loader you will need to put the appropriate quick couplers on the loader valve end of the power beyond feed to the trailer outlets.

Dan

Thanks a lot Dan for the circuit explanation and the replumb alternative. We knew that sticking a can of beans between the fender and the remote to keep it open was not the best of ideas...

I'll try to unstuck the valve first and will then for sure use your idea to feed the trailer valve.

 

[TheOldHokie]

Thanks a lot Dan for the circuit explanation and the replumb alternative. We knew that sticking a can of beans between the fender and the remote to keep it open was not the best of ideas...

I'll try to unstuck the valve first and will then for sure use your idea to feed the trailer valve.

You are welcome and this is a common issue with Kubota loaders. The 3pt valve can stall the loader as well.

The owners manual should have a good picture and description of the ports on the loader hydraulic outlet block. If you need to remove the loader you will need to diuplicate the original loop back connections for the trailer supply circuit.

Dan

 

[rbargeron]

Good discussion - reading the original post I was assuming the return from the trailer was going to the second port on the remote? Did you happen to try connecting to the other remote (if there are 2) ?

Dan is right that the trailer will perform best if its valve is fed by the tractor's power-beyond hose. The 3-pt will be disabled while connected to the trailer (not usually in issue - especially with a backhoe).

Edit: If the trailer has a PB port, a 3 hose setup as Dan describes would allow everything to work.

Dick B.

 

[TheOldHokie]

Good discussion - reading the original post I was assuming the return from the trailer was going to the second port on the remote? Did you happen to try connecting to the other remote (if there are 2) ?

Dan is right that the trailer will perform best if its valve is fed by the tractor's power-beyond hose. The 3-pt will be disabled while connected to the trailer (not usually in issue - especially with a backhoe). Dick B.

If plumbed as I described the 3pt and remotes will still work with the trailer connected. Flow will be out power beyond, through trailer valve and back to implement return on the tractor hydraulic block. The tank return on the trailer valve is being used as a power beyond. Not according to Hydraulic Hoyle but most commodity valves will tolerate it. If you wanted to do it "right" you would convert the trailer valve to power beyond and use three couplers.

Dan

 

[OliG]

Good discussion - reading the original post I was assuming the return from the trailer was going to the second port on the remote? Did you happen to try connecting to the other remote (if there are 2) ?

Dan is right that the trailer will perform best if its valve is fed by the tractor's power-beyond hose. The 3-pt will be disabled while connected to the trailer (not usually in issue - especially with a backhoe).

Edit: If the trailer has a PB port, a 3 hose setup as Dan describes would allow everything to work.

Dick B.

Hello Dick, I hoped you would chime in to help me again with my L3

Yes there is 2 remotes and we used mainly (only) the first one fed by the rear power beyond. We did not tried the other remote, but I guess trying this would confirm that the first valve is hung up if the second remote works slowly like the loader...?

I'll go in the woods this weekend and will be able to work on the tractor then.

Thanks!

 

[TheOldHokie]

Hello Dick, I hoped you would chime in to help me again with my L3

Yes there is 2 remotes and we used mainly (only) the first one fed by the rear power beyond. We did not tried the other remote, but I guess trying this would confirm that the first valve is hung up if the second remote works slowly like the loader...?

I'll go in the woods this weekend and will be able to work on the tractor then.

Thanks!

The remotes are probably parallel circuits so hooking up the second will also unload the first.
If you take the first one out of the stack and the loader works with the trailer disconnected you will know the valve is the culprit.

Dan

 

[OliG]

Hello,

Quick follow up on this problem, it turns out that the valve was not the culprit, it was the 3 point hitch draft pressure sensing lever (dont know how it is called) that was always activated due to a bent bracket. The 3 point would then always raise up trying to relieve pressure coming from the imaginary ground engaging implement, and when completely up it was stressing the hydraulic system so the loader was not working properly.

We unbent the bracket to get the lever in the right position and all is well now.

I dont understand why the 3ph was not raising when the trailer was connected though...

Thanks TheOldHokie for the help, we still will do the replumb to bypass the remotes.

 

[TheOldHokie]

Hello,

Quick follow up on this problem, it turns out that the valve was not the culprit, it was the 3 point hitch draft pressure sensing lever (dont know how it is called) that was always activated due to a bent bracket. The 3 point would then always raise up trying to relieve pressure coming from the imaginary ground engaging implement, and when completely up it was stressing the hydraulic system so the loader was not working properly.

We unbent the bracket to get the lever in the right position and all is well now.

I dont understand why the 3ph was not raising when the trailer was connected though...

Thanks TheOldHokie for the help, we still will do the replumb to bypass the remotes.

I thought we eliminated that but its good news and something to add to the notebook for future reference.

Dan