Volvo EC25 looking for aux foot valve bi directional plumbing for a thumb

[Hammer49]

Good morning OK I got a seal kit Took forever to come from Europe I’m going to attempt to try to make this work I’ll take the spool valve off and see what’s going on I will let you Know what happens

 

[Hammer49]

Ok so I replaced my boom element because it was hissing when trying to lift the machine off the ground that’s all fixed. So I took the old boom element apart and compared it to my aux foot valve spool it looked different so I said let me see if I can get Bi directional flow out of this auxiliary foot valve since it was the boom spool and it had Bi directional flow, so I swapped everything from boom element to aux foot valve element and I had flow out of both discharges A and B discharges without even touching the foot valve.So I changed everything back but forgot to change the pressure compensator in the middle #39 in Diagram and upon checking I had flow out of both A and B ports again without touching the Aux foot valve. Apparently 31 and 39 are different pressure compensators one has a notch that goes towards the middle of the compensator and different part number.You could see it in the picture if you compare. The one on the left is the boom element spool and the one on the right is the auxiliary foot valves spool. Once I put the the original pressure compensator back in I had no flow out of both A an B discharges. So I am back to square one with both lines off and I move the auxiliary foot valve In both directions and have flow out of both discharges I would assume not Bi directional.
I guess I would have to buy an auxiliary foot element that is Bi directional because I guess the ports must be different inside the element.That’s just a guess I really thought it was gonna work. Thanks for everybody’s help I appreciate it.
View attachment 238195

 

[Hammer49]

Here are some more pictures from the hydraulic element

 

[lantraxco]

Try hooking a small cylinder to the ports. You will always get oil out of both ports because one is pump pressure, the other is return which may be 25 psi or more back pressure.

 

[Hammer49]

Old element

 

[Hammer49]

Interesting didn’t realize that! I do have a cylinder I just have to get two hoses to try that thank you. Now that you mentioned that when I slowly did move the foot valve one way it seems like hydraulic fluid came out of the port A the top first and when I moved it the other way it seemed like it came out of port B first but then both of them interesting...
Thank you that is tomorrow’s project I’ll get this one way or another hopefully.

 

[lantraxco]

Actually after reading this on my PC rather than my phone, I have a better grasp of what you did there. Why not just swap in the complete boom element? I'm guessing the only issue with the boom element was a weak port relief valve, though I could be wrong.

 

[uffex]

Good day Hammer
Please see attached.
Kind regards
Uffex

 

[Hammer49]

Good morning I don’t think my element has a load sensing valve or is it just a port or channel that goes though the entire main block assembly, when I took it apart there was nothing above pressure compensator and the plug. Interesting I’m learning a lot. I will check this today too get back to you thank you very much. Uffex do you have a diagram of the flow with the spool moving in each direction like the one you sent me that would be interesting to look at thank you again

 

[Hammer49]

https://linksharing.samsungcloud.com/mCPNlqoxDUu2

 

[Hammer49]

So I had 2 hose made up today and put them on and low and behold the thumb works unbelievable I guess looking at the fluid come out the of the ports without actually checking it with a hose and pressure was my downfall. Also put the pressure relief valve from the old element on the auxiliary foot valve element. I appreciate everybody’s help thank you very much what a relief!

 

[Hammer49]

https://linksharing.samsungcloud.com/gAuFtMIuJSj9

 

[uffex]

Good day I guess it is for you Hammer that is good news, I assume I there is no need for any further information?
Kind regards
Uffex

 

[Hammer49]

Yes it is a good day thank you I guess this all started When I replaced the two auxiliary pipes at the top of my boom that were cut and pinched off after replacing them I operated the auxiliary foot valve and flow came out of both lines. I didn’t realize that you have flow in both lines like lantraxco said “hooking a small cylinder to the ports. You will always get oil out of both ports because one is pump pressure, the other is return which may be 25 psi or more back pressure“. So that was a big lesson learned in my mind on the actual flow of hydraulics.The illustrations of the spool was also Inspiring to me to find how everything worked inside.
Thank you to everyone

 

[lantraxco]

Glad you got it going, good job!

 

[ESDE]

Soooo, I am in almost the exact same situation, though my machine is set up a little different. I'm trying to clarify what you did here, and see if it will apply to my machine?
I have an EC25 and just installed a Manca thumb. The machine has two aux lines on the stick, and I mistakenly did not realize that one was a return as the Aux control pedal moved in two directions (so I ASSumed it was for a dual action cylinder). But, It's just a pressure and return, so I have no way to retract the thumb.
Did you change the spool in the valve to make it work in both directions? What else?
I imagine I will either need to run a second line to the thumb, or plug the return at the tank and use that line. That's fine as I don't ever see myself using a hammer or tool needing continuous flow.
Thanks in advance, I read this a few times but am still a little confused.
SD

 

[ESDE]

I should've dug into may machine before posting..
Traced the lines, the aux spool has two lines going out to the boom. One is capped and the other goes out to the stick. I cracked the cap and I get oil when the pedal is rocked back. Looks like I need a hose and I'll be in business. Fingers crossed