Finding point of failure - diverter valve or FEL control valve

[ljplum12]

When you were checking your pressures, was that at the main line going to the loader valve? Or was that at one of the outlet hoses going to a cylinder?

Check it at an outlet port going TO a cylinder. IF you are getting 2000psi, that should be more than enough to raise the loader.

It was on main line going into the loader valve. I'll check it at the cylinder.

 

[Bob Rooks]

Maybe I missed it, but I didn't see where anyone explored the possibility of blown cup seals in one or both lift cylinders.

 

[LD1]

Certainly ain't ruling that out, but trying to check the easy stuff first.

 

[ljplum12]

ljplum,
At this point we don't care about steering, etc. We are trying to do fault isolation on only the FEL valve.

Let's continue:
Set tractor RPM at about 1200.
Now curl the bucket till it stops. (when it reached mechanical stop, did gauge show 2000psi?)

Now open the bucket till it stops. Relief valve should open at 2000psi. (when it reached mechanical stop, did gauge show 2000psi?)

Now press the lever to raise the FEL. Tell us specifically what happens and what the gauge shows at each action.

When I curl the bucket towards the tractor it goes up to about 2100psi. When I tilt the bucket up it goes to 1500psi. This is with the gauge at the inlet side of the FEL valve.

 

[erj]

ljplum,
We need to be sure that we are using the same terminologies.

Place your hand on a table with your palm up. Curl your fingers. When you raise the front lip of the FEL bucket, it is called curling. Uncurl your fingers. When you lower the front lip of the FEL, it is uncurling.

I would like you to repeat this slightly differently just to verify the 600psi difference you saw in the relief pressures.

Set tractor RPM at about 1200.
Now CURL the bucket till it stops and hold it for a couple of seconds. (what was highest reading on gauge?)

Now UNCURL the bucket till it stops and hold it for a couple of seconds. (what was highest reading on gauge?)

 

[ljplum12]

ljplum,
We need to be sure that we are using the same terminologies.

Place your hand on a table with your palm up. Curl your fingers. When you raise the front lip of the FEL bucket, it is called curling. Uncurl your fingers. When you lower the front lip of the FEL, it is uncurling.

I would like you to repeat this slightly differently just to verify the 600psi difference you saw in the relief pressures.

Set tractor RPM at about 1200.
Now CURL the bucket till it stops and hold it for a couple of seconds. (what was highest reading on gauge?)

Now UNCURL the bucket till it stops and hold it for a couple of seconds. (what was highest reading on gauge?)

I verified. By that definition when I CURL the bucket, it's hits 1500psi max. When I UNCURL the bucket it's 2100psi.

 

[erj]

ljplum,
Let's itemize what we have learned so far:

1. The hydraulic pump seems to be OK. It can produce at least 2000psi when needed.
2. The relief valve appears to be OK. It can be adjusted to release pressure when reaching 2000psi.
3. The bucket curl function works somewhat, but relief valve releases pressure when reaching only 1500psi.
4. The bucket uncurl function works and relief valve releases pressure at 2100psi.
5. Item 3 indicates that there may be a problem in the FEL spool controlling bucket curl/uncurl or downstream in the hydraulic cylinder.

Now let's check the raise/lower spool:

If possible, place the tractor so the FEL is over some firm ground or concrete.
Set tractor RPM at about 1200 and release the brake with transmission in Neutral.

Now UNCURL the bucket till it stops and hold it for a couple of seconds. (what was highest reading on gauge?)
This should have either raised the front of the tractor or caused the FEL to raise. (which one happened?)

Now move the lever to lower the FEL until it stops and hold it for a couple of seconds. (what was highest reading on gauge?)

Now move the lever to raise the FEL. Tell us specifically what happens and what the gauge shows at each action.

 

[ljplum12]

ljplum,
Let's itemize what we have learned so far:

1. The hydraulic pump seems to be OK. It can produce at least 2000psi when needed.
2. The relief valve appears to be OK. It can be adjusted to release pressure when reaching 2000psi.
3. The bucket curl function works somewhat, but relief valve releases pressure when reaching only 1500psi.
4. The bucket uncurl function works and relief valve releases pressure at 2100psi.
5. Item 3 indicates that there may be a problem in the FEL spool controlling bucket curl/uncurl or downstream in the hydraulic cylinder.

Now let's check the raise/lower spool:

If possible, place the tractor so the FEL is over some firm ground or concrete.
Set tractor RPM at about 1200 and release the brake with transmission in Neutral.

Now UNCURL the bucket till it stops and hold it for a couple of seconds. (what was highest reading on gauge?)

Highest reading was 2100psi when I got it all the way uncurled.

This should have either raised the front of the tractor or caused the FEL to raise. (which one happened?)

It raised up the FEL.

Now move the lever to lower the FEL until it stops and hold it for a couple of seconds. (what was highest reading on gauge?)

It read right around 2000psi. You can hear the pump bog down but the cylinders don't move.

Now move the lever to raise the FEL. Tell us specifically what happens and what the gauge shows at each action.

Same as trying to lower the FEL. Pump bogs down, pressure goes up to 2000psi but the loader doesn't move.

 

[erj]

ljplum,
Let's itemize what we have learned so far:

1. The hydraulic pump seems to be OK. It can produce at least 2000psi when needed.
2. The relief valve appears to be OK. It can be adjusted to release pressure when reaching 2000psi.
3. The bucket curl function works somewhat, but relief valve releases pressure when reaching only 1500psi.
4. The bucket uncurl function works and relief valve releases pressure at 2100psi.
5. Item 3 indicates that there may be a problem in the FEL spool controlling bucket curl/uncurl or downstream in the hydraulic cylinder.

6. The bucket lower function did not work and relief valve releases pressure at 2000psi.
7. The bucket raise function did not work and relief valve releases pressure at 2000psi.
8. Items 6 & 7 indicates a problem in the FEL spool.

The next thing that I would do is to check out the FEL spools. I am not familiar with the Pace model FEL valve, but the valves generally work the same way. Below is a picture of a spool and the chamber that holds it from a Prince valve that may help you. The 2 spools should be checked to see if they are clean and if the chambers are clean.

Also if you want to send me a PM (private message) with your Email address, I can send you a PDF file that describes the internal workings of a FEL valve.

 

[Bavarian]

Are there any quick connectors between the valve and the loader? They might be loose or damaged.

 

[Bob Rooks]

Are there load checks in this particular valve? Many loader valves have them.
This is what makes me think of blown cup seals - "3. The bucket curl function works somewhat, but relief valve releases pressure when reaching only 1500psi. Because the oil is by-passing the piston. The resistance required to create pressure is limited. I don't believe the lower pressure you're seeing is the relief popping. There should be a squealing or hissing sound coming from the valve if it's releasing. There will be a hissing sound coming from a cylinder if the seals are by-passing.
4. The bucket uncurl function works and relief valve releases pressure at 2100psi. Because the piston is at the end of it's travel, and the cup seal is up against the cylinder end."
Just my two cents because I've experienced this first hand.

 

[ljplum12]

Are there load checks in this particular valve? Many loader valves have them.[\QUOTE]
I don't know the answer to this. How would I find that out?

Is there a way to verify blown cup seals without tearing into the cylinder?

 

[ljplum12]

Are there any quick connectors between the valve and the loader? They might be loose or damaged.

No, there are no quick disconnects besides the main in/out connections.

 

[LD1]

Is there a way to verify blown cup seals without tearing into the cylinder?

Yes but its messy.

First, EXTEND the cylinders all the way (Dump the bucket). Remove the rod side hose. Try to dump again.....if oil comes out the cylinder where you just removed the hose....bad seals. If no oil comes out, seals good.

 

[Bob Rooks]

First, EXTEND the cylinders all the way (Dump the bucket). Remove the rod side hose. Try to dump again.....if oil comes out the cylinder where you just removed the hose....bad seals. If no oil comes out, seals good.

Actually, you want to extend in the direction that you were getting the low pressure reading, whichever that was.

 

[ljplum12]

Actually, you want to extend in the direction that you were getting the low pressure reading, whichever that was.

The low pressure is when I'm curling the bucket, so do I still remove the hose on the rod side? How do I check the lift cylinders?

 

[Bob Rooks]

How do I check the lift cylinders?

The same as the tilt cylinders. Lift the bucket until the relief valve squeals or hisses. Lower the bucket flat on the ground and lift the front of the tractor until the relief valve squeals or hisses. If the indicated pressure is the same in both directions, and the lift arms hold in both directions, the cup seals are fine. Something I forgot to ask, do you have the regen feature on your loader valve?

 

[Bob Rooks]

The low pressure is when I'm curling the bucket, so do I still remove the hose on the rod side?

I don't know how your cylinders are mounted so I can't say without seeing a picture.

 

[ljplum12]

The same as the tilt cylinders. Lift the bucket until the relief valve squeals or hisses. Lower the bucket flat on the ground and lift the front of the tractor until the relief valve squeals or hisses. If the indicated pressure is the same in both directions, and the lift arms hold in both directions, the cup seals are fine. Something I forgot to ask, do you have the regen feature on your loader valve?

I can't actually lift the bucket unless I back up the pressure by turning the steering wheel.

If the bucket is on the ground and I try to either lift the bucket or go down to lift the front of the tractor, the cylinders don't do anything and the pressure goes to 2100psi. There is no regen on the valve that I can tell.

 

[Bob Rooks]

Regen is a detent that you go through when you dump the bucket. The bucket dumps very quick. Back in a few.