Volvo EC 25 question

[SinNH]

Hi first post here, thanks in advance for any help.
I bought a EC25 a couple years ago with 1700 hours, now 2100, no major issues at all.
I'm in the process of installing a new thumb and cylinder, and was told that the plumbing out to the stick was set up for a thumb, it had used quick disconnects on the lines.
The valve element that the foot rocker operates for the accessory is controlled by a cable which functions fine.
The feed line ( push piston out ) comes directly from the valve, but the larger line ( return ) first connects to a block by the spool valve and from that block to the other end of the accessory valve.
When I operate the foot rocker, no matter which way, it pushes out he piston, reverse the lines, same thing.
I didn't mess around with it much, because I did not want to push the piston to the "out stop".
It seems to me that the hydraulics from the factory ( every pic on the internet seems to have those two lines on the left side of the boom/stick) is set up for a saw or hammer needing constant flow. I do not find any valve, etc to change the set up. There are no unused switchs in the cab.
Any thoughts?
Thanks
Steve

 

[lantraxco]

Picture of the block? Look for something on that block that can be turned (hex head rotary spool) or shifted (spool with a lock) to change flow from direct to tank over to the flow through the accessory valve. Guessing.

 

[Orgera]

I have the same problem
I want to use my auxiliary hydraulics to power another piece of machinery
I'm told if it does not have a sheer valve setting it will not work
I'm sure there is a way to bypass something hopefully someone can answer

 

[lantraxco]

I have the same problem
I want to use my auxiliary hydraulics to power another piece of machinery
I'm told if it does not have a sheer valve setting it will not work
I'm sure there is a way to bypass something hopefully someone can answer

Do you have auxiliary hydraulics already installed on the machine?

 

[Orgera]

Yes I have auxiliary hydraulics on the boom

 

[lantraxco]

Yes I have auxiliary hydraulics on the boom

So, where's the problem? If you're powering something with it's own valves, I would assume you need pressure and return lines, and that's what you got. Hammer setting should be fine, not sure if you have a foot pedal, button switch or whatever, just have to find a way to keep it on.

 

[Orgera]

So, where's the problem? If you're powering something with it's own valves, I would assume you need pressure and return lines, and that's what you got. Hammer setting should be fine, not sure if you have a foot pedal, button switch or whatever, just have to find a way to keep it on.

I have very limited knowledge on hydraulics
I'm told that the auxiliary lines are not a continuous flow
I don't have a problem wedging a stick on the footpedal if need be
In my mind it should work
The drilling unit I want to purchase has its own control valves forward and reverse
Enclosed is the spec sheets for my machine
http://d3is8fue1tbsks.cloudfront.net/PDF/Volvo/Volvo EC25-EC30 Mini Excavator.pdf

 

[lantraxco]

Exactly, the brochures says it comes standard set up and plumbed for a hammer, that is one pressure line and a direct return to tank. As you say, put a brick on the pedal or wedge a stick on it, should be okay. Looks like 11.89 gallons per minute flow at 3,335 psi.

 

[Orgera]

Awesome thank you so much!
I'll let you know how it works out

 

[kthompson]

I have ec45 and the line if plumbed it sounds same as yours. I have used cutter on mine and it is only one direction pressure as has been said. I not sure that valve will hold pressure to keep the thumb in place and do not think you want to keep the valve open as it is taking power to do that. When I am running my cutter it takes so much gpm it leaves little for other operation.
Had friend to tell me might be able to use springs to pull the thumb up but if the valve does hold pressure no idea how you could pull it up unless you had an electrical valve that switches the plumbing on the boom.

 

[melli]

I don't know...it says it comes standard with a one way circuit to tank for a hammer, but not two way.
Brochure says 'Optional' "Hydraulic circuits for attachments
Hydraulic circuit for double-acting
attachments (auger, thumb...)."

I think you need to tweak the one way setup. I have both options on mine. A switch changes between the two. When I have it on hammer mode (one way), the thumb wants to close, then relief kicks in. Not the way one wants to use a thumb.
No idea what is involved...looks like a electrical solenoid activated valve that switches between one way and two way.
I seem to have two electrical solenoid valves on manifold...

 

[Orgera]

I'm going to be running a separate piece of machinery with the auxiliary hydraulics valve
The drilling machine I'm running use to have it's own separate motor,pump and tank so I believe all I need is a supply line to the valve controls on the unit then a return line to the tank

 

[kthompson]

I went with a mechanical thumb on mine and it was built by local shop who builds and installs them for large machines. Has worked very well. Would it be better if it were on its own hyd cylinder, sometimes it would be but not worth the cost to installed the circuit it needs, for me. If it is designed correctly the thumb and the stiff kneee to lock in place all remain folded under the boom when not needed. For the size of the machine we are talking about do not forget how little the thumb really weighs for most people a one person install or removal. Mine is heavy enough I like a second person to push the pin in place if it was removed but no issue to lower the boom so the weight of the thumb remains on the ground while you install the pivot pin. Will say if you have one properly designed to use the stiff knee, you can replace it with hyd cylinder when you get the circuit in place for it. One thing will add every line, wire or what ever you run on the boom you are still installing a little more weight and little more to get caught in trees or what ever. I do remove my thumb when I am totally doing major digging for the clearance and the weight factor. Again small machine needs no extra weight on it.