John Deere 225D Excavator Thumb settings

I have a 2012 John Deere 225D excavator. Recently purchased. It is bending the thumb cylinder. I am not sure if its that I am not choosing the correct attachment on the operator screen? Also I have tried looking up how to check pressures and which valve to adjust but with no luck. Is there anybody that has any experience with this particular machine . Thanks

Welcome to HEF J&L ! The circuit relief for the barrel end of the thumb should be set to approximately 1700-1800 psi (11.7-12.4 MPa). It has to be able to collapse when the bucket pushes against it. Follow the line from the barrel end to the control valve. The circuit relief will be either on top of or just below on the control valve, depending on how it was plumbed. Post a picture of the thumb just to make sure the thumb was installed correctly. The pressures can be read in the monitor. Check your messages.

mg2361, Thank you for the welcome and the response. I have accessed thru the service menu on the monitor and it only shows the pressures for both in and out functions to only be at about 4 MPA or slightly lower which is super low. which makes it think this is the pilot control pressures. Correct? I will try and get a picture of the thumb asap. I Believe it came with the thumb as John Deere shows it under the vin#. It is plumbed barrel end to the line on the passenger side and Cylinder end on the drivers side of the boom. hopefully that makes sense. Also it doesn't seem to change pressures when I change attachment settings on the monitor the only thing I can tell is that on attachment #2 I believe it says it opens the secondary relief valve or something like that. it does not have a choice in the attachment selection for a thumb it just shows crushers. So I am not even sure which setting to run it on. I bought the Technical and operations test manual but Couldn't find anything in there either. I may need to buy a different manual but not sure which one. Thanks again for your help.

Here’s some pictures I hope this is what you’re thinking. The picture of the plumbing with the valve would be the barrel end of the thumb cylinder. I also believe that valve is for switching from one way and 2 way is that correct?

You are watching delivery pressure in the monitor? 4 MPa sounds like control pressure. Any theory on the auxiliaries is found in the hydraulic theory section. It will not explain any detail on any particular attachment. Even though the machine may have come with the thumb, it is not Deere installed. It is installed by the dealer. In the monitor, watch the pump 2 delivery pressure. What does it read when you extend the thumb cylinder out against its stop, over relief? For the thumb, you can leave the machine in regular dig mode and not select any particular attachment. Any attachment selection that allows two way flow would also work. J&Lrepair said: The picture of the plumbing with the valve would be the barrel end of the thumb cylinder. I also believe that valve is for switching from one way and 2 way is that correct? Click to expand... The valve I think you are referring to (picture below) is not normally used in our auxiliary hydraulic setup. Please provide the machine's serial number so I can see what options your machine has.

mg2361 said: You are watching delivery pressure in the monitor? 4 MPa sounds like control pressure. Any theory on the auxiliaries is found in the hydraulic theory section. It will not explain any detail on any particular attachment. Even though the machine may have come with the thumb, it is not Deere installed. It is installed by the dealer. In the monitor, watch the pump 2 delivery pressure. What does it read when you extend the thumb cylinder out against its stop, over relief? For the thumb, you can leave the machine in regular dig mode and not select any particular attachment. Any attachment selection that allows two way flow would also work. The valve I think you are referring to (picture below) is not normally used in our auxiliary hydraulic setup. Please provide the machine's serial number so I can see what options your machine has. View attachment 363530 Click to expand...

It doesn’t show any delivery pressure on either pump on any function.

Here’s the vin tag

In your 3rd picture, it shows the crossover for the thumb extend circut. in that block, there looks like an adjustable square headed valve, that looks like it either had a handle on it or been moved with an adjustable wrench? Is it possible that the way it was plumbed, that is a pressure relief valve for the thumb pressure? Edit to add, it looks like there is a stop on it, so it may just be a shut off valve.

Ya there just shut off valves

Interesting. Under the hydraulic pump delivery lines, are there pressure sensors there?

I’m about to go look for some sensors not sure where to look though lol I’m guessing right on the pumps

mg2361 said: View attachment 363554 Click to expand... It looks like it to me

Then you should be able to see pressures in the monitor. I wonder if both sensors are defective? So for now, to fix your thumb cylinder bending issue, you either have to plug a gauge into the sensor port on the pump to the left, or tee a gauge into the barrel end of the cylinder to adjust the circuit relief pressure. Then I would work on diagnosing those sensors because they can affect the operation of the machine.

mg2361 said: Then you should be able to see pressures in the monitor. I wonder if both sensors are defective? So for now, to fix your thumb cylinder bending issue, you either have to plug a gauge into the sensor port on the pump to the left, or tee a gauge into the barrel end of the cylinder to adjust the circuit relief pressure. Then I would work on diagnosing those sensors because they can affect the operation of the machine. Click to expand... Where is the circuit relief valve located for the Thumb? Am I just adjusting the relief for the thumb or that whole bank ran off that pump? Thanks again you have gotten me further than anybody else.

You will only adjust the relief for the barrel end of the cylinder. I sent you a personal message a couple of days ago with the relief locations. Check the little envelope near the top of the page next to your username. The picture I had sent you only shows plugs in the ports, but reliefs should have been added when the auxiliaries were installed. You will have to follow the barrel end line to the control valve to know which relief to adjust, or post a picture of the control valve from a bit further away than the above pictures you posted. Then indicate which line is the barrel end line. Below is where to find messages.

mg2361 said: You will only adjust the relief for the barrel end of the cylinder. I sent you a personal message a couple of days ago with the relief locations. Check the little envelope near the top of the page next to your username. The picture I had sent you only shows plugs in the ports, but reliefs should have been added when the auxiliaries were installed. You will have to follow the barrel end line to the control valve to know which relief to adjust, or post a picture of the control valve from a bit further away than the above pictures you posted. Then indicate which line is the barrel end line. Below is where to find messages. View attachment 363636 Click to expand... Ok so I got to spend some more time on it this weekend. Had a broken power wire going to the delivery pressure sensor on pump 1. A bad sensor on pump 2. But it looks like the main problem is that they never installed pressure relief valve on initial thumb install as all I see is plugs on top and bottom. So if I understand correctly I need to get a pressure relief valve for the bottom side where the barrel end is plumbed correct? In the pictures that’s the bank for the thumb with the purple zip tie you can see the plug on top. Has the same plug on bottom. Barrel end is plumbed to bottom hose.

Yes, you would need a relief valve. We install reliefs in both ports because that is what our kits come with. Plus it is a good idea for circuit protection. Relief part number is 4309832.

Mg2361. Just wanted to thank you again. got my relief valves in today and everything is working perfectly

You're welcome. Glad to hear you are up and running.