Grey market FEL on L1-24 Sunshine

[torch]

Should I cap both legs

NO! Capping both would dead-head the pump. That is, the fluid being pumped would have no where to go. Pressure would skyrocket instantly and something would burst!

Just cap off the line to the FEL. If the 3ph suddenly starts working properlly, then you have confirmed that they incorrectly tapped the 3ph pressure line.

 

[North Idaho Wolfman]

Doesn't the FEL valve have Quick disconnects on the line that go to and come from it?
if it does just disconnect one side ot the other and that will isolate the FEL from the system.

I do believe that the only reason it works at all is there appears to be a pressure relief valve on the out line of the FEL, thus creating a second loop, thus robbing flow to the three point control.
Really bad way to try hook it up!

 

[Crazy Horse]

There's a quick coupler yes, so just unhooking that will accomplish what we are trying to do in the test?

 

[North Idaho Wolfman]

There's a quick coupler yes, so just unhooking that will accomplish what we are trying to do in the test?

Yes it will, because it will isolate the valve out of the hydraulic system.

 

[torch]

Doesn't the FEL valve have Quick disconnects on the line that go to and come from it?

Good point!

 

[Crazy Horse]

Hey guys, so I forgot to pick up a cap for the line, but I did a little test:
I disconnected the supply side of the fel, (uncoupled the quick coupler)no change in the 3point hitch speed.
Still slow picking up.

So I unscrewed the quick coupler off of the supply side to check for pressure, it had a good flow. I don't know if it's supposed to come out under pressure, it didn't, but it had a pretty fast flow.


Then I unscrewed the return to tank quick coupler off and started the tractor, and without moving the control valve I had about the same flow out of that hose as I did the supply.
I don't know if there's an automatic bypass built into the control valve, or if the seals are bad. But, with the supply disconnected I could manipulate the control valve to let down the boom at much faster rate. Now it wasn't nessesarily faster when I pulled it all the way to the lower boom setting, but rather when I kind of just pulled it about halfway and jiggled it around, it released at what I would consider a normal rate.
So i guess the questions are:
is the return to tank line clogged, is it sucking air, or is the control valve shot/ the wrong one?


Also, when I disconnected the return to tank coupler it still picked the boom up.

 

[torch]

Hey guys, so I forgot to pick up a cap for the line, but I did a little test:
I disconnected the supply side of the fel, (uncoupled the quick coupler)no change in the 3point hitch speed.
Still slow picking up.

Odd. So much for the parallel circuit theory then.

So I unscrewed the quick coupler off of the supply side to check for pressure, it had a good flow. I don't know if it's supposed to come out under pressure, it didn't, but it had a pretty fast flow.

Pressure doesn't build until there's something to push against. Like putting your thumb over the end of the garden hose.

Then I unscrewed the return to tank quick coupler off and started the tractor, and without moving the control valve I had about the same flow out of that hose as I did the supply.
I don't know if there's an automatic bypass built into the control valve, or if the seals are bad.

That is expected behavior for an open center spool valve.

But, with the supply disconnected I could manipulate the control valve to let down the boom at much faster rate. Now it wasn't nessesarily faster when I pulled it all the way to the lower boom setting, but rather when I kind of just pulled it about halfway and jiggled it around, it released at what I would consider a normal rate.
So i guess the questions are:
is the return to tank line clogged, is it sucking air, or is the control valve shot/ the wrong one?

It sure sounds like something is restricting the return flow to the tank.

Also, when I disconnected the return to tank coupler it still picked the boom up.

Yes, it would.

 

[Crazy Horse]

Hey guys, do you think maybe I just need to swap the lines on there respective valves, that they may just be on backwards?

 

[torch]

Setting aside relief valve operation for a moment, it shouldn't make much difference other than the controls would be reversed -- boom up for boom down and bucket curl for bucket dump. If there is a regen feature, that would probably quit working though. In fact, a regen position would dead-head the pump and cause damage since there would not be a relief valve in the circuit.

Too bad we can't ID that control valve and verify the ports. I'm sure we are missing something here.

 

[Crazy Horse]

I'll look it over more closely tonight

 

[Crazy Horse]

Nothing else on the control valve, just the numbers posted above. It does have a little knob on the control on the side toward the operator, with some Japanese writing on it. Since there's another one on the boom cylinders with the rabbit/turtle on it I assume that's what it is, and i tried adjusting them around to no effect.

 

[Crazy Horse]

Hey guys, correct me if I'm wrong:
So there's a tee in the supply line for the FEL. The other leg of the tee goes to the rear end, tapping in there. If that's just returning to the reservoir that's where the problem is, that's why I have no pressure, as it would be stealing pressure from the supply. The diagram I saw in the service Manuel seems to suggest that the 3ph is getting its pressure from the fitting under the seat, next to the speed control valve for the 3ph. Let me know if I'm on the right track guys, I'm going to try this tomorrow evening, so if I'm about to blow something up it'd be nice to know

 

[torch]

Hey guys, correct me if I'm wrong:
So there's a tee in the supply line for the FEL. The other leg of the tee goes to the rear end, tapping in there. If that's just returning to the reservoir that's where the problem is, that's why I have no pressure, as it would be stealing pressure from the supply. The diagram I saw in the service Manuel seems to suggest that the 3ph is getting its pressure from the fitting under the seat, next to the speed control valve for the 3ph. Let me know if I'm on the right track guys, I'm going to try this tomorrow evening, so if I'm about to blow something up it'd be nice to know

It's supposed to be a series circuit -- the input to the 3ph is interrupted and re-routed to the FEL control input first. Then the FEL control "Power beyond" port feeds the 3ph input. Finally, a third line runs from the FEL control to the tank.

When the FEL control is centred ("neutral"), the fluid flows unrestricted through the FEL control input and out the PB to the 3ph. If the 3ph control is centered, then the fluid continues on through to the tank. If the 3ph control is moved to lift, then fluid is diverted to the 3ph piston and prevented from returning to the tank -- building pressure to the limit of the relief valve setting. The relief discharges excess fluid back to the tank. If the 3ph control is moved to lower, then fluid from the piston is also returned to the tank along with the recirculating flow.

Now, when the FEL is actuated, flow is cut off from the PB outlet and used to pressurize the respective cylinders for the function desired to the limit of the FEL relief valve setting. The relief discharges excess fluid back to the tank via the third line mentioned earlier. That third line also returns fluid coming from the other, unpressurized, end of a double-acting cylinder when the cylinder is operated.

 

[North Idaho Wolfman]

Let me see if I can help clarify what is going on with your tractor.
Yellow lines are Suction
Purple lines are High Pressure
Greens lines are Low pressure returns


This is a simple hydraulic system with the three point control.

This is if you added a simple loader or any simple spool valve.

This a newer spool valve with power beyond control.

This is the way your tractor is set up right now.
It's not 100% wrong, but it has the inability to be easily maintained or controlled due to having 2 relief valves trying to maintain control of the High pressure circuit.

Your aftermarket relief valve.

 

[North Idaho Wolfman]

Let also clarify what is going on with the tractor.

Does the loader work properly?
Fast and smooth and with good strength?
If not there are a ton of possibilities of what is the root cause of the problem is and it will take some digging to get to the bottom of it.

Three point you say is slow, have your tried messing with the electric switches and dials? As I'm not 100% sure but I think one set of controls might effect speed of three point lift.
This being a grey market tractor, as I stated before, has both mechanical and electrical control over the hydraulic system.
The system is called monro matic if I remember right.
So it's possible that everything hydraulically is working right and possibly a electrical dial or switch setting is just wrong.
The other simple possibility is that a feed back rod or sensor is not adjusted right and that is the issue.

Also if the loader is working right, then you can use a pressure gauge to easily check the pump pressure and that will confirm that is operating to pressure.

 

[torch]

This is the way your tractor is set up right now.
It's not 100% wrong, but it has the inability to be easily maintained or controlled due to having 2 relief valves trying to maintain control of the High pressure circuit.

Well no wonder things don't work right! If it's trying to force the returning fluid through a relief valve on the way to the tank then that's the restriction in the return line! Returning fluid has to force the relief valve open. It would explain why things work right when he disconnected the return line.

A relief valve should be piped so as to bypass the FEL control if the set pressure is exceeded (ie: pressure side to relief inlet, relief outlet to tank side).

 

[North Idaho Wolfman]

Well no wonder things don't work right! If it's trying to force the returning fluid through a relief valve on the way to the tank then that's the restriction in the return line! Returning fluid has to force the relief valve open. It would explain why things work right when he disconnected the return line.

A relief valve should be piped so as to bypass the FEL control if the set pressure is exceeded (ie: pressure side to relief inlet, relief outlet to tank side).

No, on kubota's they are an open loop system, all fluid flows thru the pressure relief valves not around them, you need the relief valve as that is how the system builds pressure, otherwise you just have flow with no pressure.

The system you are thinking of is a closed loop system, like an old John Deere system.

The problem with the way his is setup is that they have 2 relief valves in the system and the one with the lower setting wins the battle, so most likely the added aftermarket valve is lower thus sending the flow thru the loader control valve and thru that added relief valve and to the sump thus robbing the flow thru the 3 point control.

 

[Crazy Horse]

Help me understand this guys, the line coming off of the spool valve is going to a fitting under the seat next to the 3ph speed control valve, as pictured above somewhere. Is this the pressure supply for the 3ph, and it has an internal pressure release valve?

If this is the case isn't that line that goes to the rear end unessesary, and probably the issue?
Can I cap that line and see what happens?


Yes, it does have electric controls on the fender for a cylinder to adjust the "height" of one arm of the 3ph, in other words it can possibly drop one arm lower than the other. At least that's what it looks like.

Also, the fel does not function properly, it picks the boom up at a good speed, and also dumps the bucket at a good speed, but lowers the boom and curls the bucket very slowly, and also does not have a lot of power, it barely picks the tractor up when I drop the bucket against concrete, also I tried picking up some material with it and it wouldn't pick it up or lift the rear end of the tractor off of the ground.


Below is a drawing of what is on my tractor, minus that little pressure valve on the rear end line

 

[North Idaho Wolfman]

Ok, now with that drawling makes no since at all!

Are you 100% sure that the control valve for the loader is hooked up like that?

Take a paint pen and start at the output of the pump and follow the line back, when you hit the tee paint to the valve then go back to the tee and paint it till it gets to the end!

If the Tee does go to the side of the rear end with the AM PRV on it then I'm at a loss to explain why they would have done that!

My Impression: The tee in the line looks like its on the line that goes under the seat to the round fitting with 2 bolts under the seat, which is the input line for the hydraulics to feed the three point control and factory pressure relief valve.
The line on the side of the rear end with the aftermarket pressure relief valve should be the return line the dumps into the rear end.

 

[Crazy Horse]

So I took the line on the tee going to the rear end out and capped it