We have a Volvo EC240CL vin #VCEC240CV00110691. When I curl the stick inward, the machine slowly will begin to turn left and there is reduced power because of hydraulic pressure going in two functions. I capped the hydraulic lines at the joystick for the turn function, and it still does the same thing. That wound leave the control valve as a possible problem. Any other suggestions on isolating this problem would be greatly appreciated. I am not sure which valve would be at fault, but diagrams and suggestions would be a great help. If there is anywhere else to test, please inform me. Thanks in advance. Mike
Look in the cabinet immediately behind your cab. Do you have a pattern change valve? Is it all the way one way or the other? Pattern change usually only affects boom n arm, but weirder things have happened.
Pattern changer is all the way in position. That doesn't mean it is good. We changed it's position and got no difference. If the control valve assy had a broken spring in one of the valves, i'm thinking that would cause it not to close off and allow pressure from another valve.
On the C series you can pull up pilot pressure for all functions in the service mode of the monitor. First, again, plug the pilot hoses leading to the spool caps at the MCV swing spool. Leave the caps open to atmosphere. Remove the caps and i spect the centering springs as well as the retainer. Any broken coils, loose retainer? If everything is good, put the caps back on, fittings open to atmosphere again. Pull up service mode, scroll through and find your pressure sensors for the functions. Observe swing pressures while arming in to dead head and the same in arm out. Have an assistant (IN A SAFE PLACE) Observe the open spool caps. If oil squirts out, your MCV is most likely either scored or cracked. If no oil, and no function, time to evaluate the RCV. Good luck.
Would someone have a diagram of which control valves are for the arm, in and out, and which ones are for the track turn left?
track or slew ?
try this.
Sorry, just the body is turning left, not the track driving it.
So the slew rotates the cab to the left only when the stick is brought inward and with little hydraulic power making it impossible to do work
I could not find pilot pressure in the service menus. I located the arm control and capped the lines. There was still slew movement to the left even though the arm couldn't move when the controller was activated for the arm. I pulled the valve out and checked it. All looked good, no scratches and sprin and retainer are good. I capped off lines to what I believe to be the slew valve, and the cab would only turn right, not left. I pulled the valve out and all looks good. No scratches and spring and retainer look good. I am now suspect of the pattern changer. I will attempt to bypass it tomorrow. Does this make sense, or am I missing something? I cannot check pressures until I can find them in the menu. I looked under Hydraulics. Also how do I get the sensor pressures to come up in service menu?
Turn key on, do not start. Press and hold the wrench button till the screen says "entering service mode" press the enter key. In service mode the wrench symbol will be shown on the bottom of the display. Scroll down to hydraulics, it will show you pump pressures and all your pilot pressures, you just have to navigate the screens. Let me remind you. The pattern change valve only swaps boom and arm from side to side. Swing is completely isolated from pattern change. The only connection is the RCV or joystick.
The EC240C is negative control and does not have pilot sensors so there will be no menu for pressure in the IECU. When you say the house is swinging to the left is it always to the left? Is it moving under power or a drift and is it only arm in that you see the complaint? The arm in circuit does release the swing brake so the house is capable of moving when arming in. If not on level ground it can drift one way or the other. The swing pilot lines should be a direct shot to the spool caps on the MCV so unless someone has had lines off and crossed up or added lines that should be OK. The only way to check pilot pressure to each function is to tee into the line with gauges. The most likely explanation is that the RCV is being manipulated in both directions at the same time.
I am still hunting for the hydraulic problem. The crowd movement of the stick still bleeds pressure into the swing left function enough to allow a slow turn of the cab left. It also reduces digging capabilities. I have pulled both the swing and stick valves from the main valve assy, and they appear perfect. I have capped off the joy sticks one at a time for the swing lines, and it still does it. When I cap the crowd or stick in line, it stops movement, so somewhere pressure is leaking into the swing function. I followed the stick control line down to a block under and behind the main valve assy, and capped a couple lines coming out of the block. The swing movement again stopped. I rebuilt the block with new O rings, but found nothing that would suggest a failure. That's as far as I have gotten. I will put the block back in tomorrow and cap each line one at a time. If it still moves the swing, I will trace that line to see where it goes.
The arm in and the slew left and slew right may interconnect via a bad or leaking shuttle valve which is used to signal a pilot pressure to release the swing brake on the SH port of the swing brake valve on the side of the swing motor. These shuttle valve can sometimes be a T style hydraulic fitting with a ball bearing and seat arrangement inside. Kind regards
There are two such valves coming from the block under and behind the main control assy. I plugged the one with a T style fitting which did have a ball bearing and seat inside ir. The line straight off the end of the T goes to the end of the manifold assy where the joy stick hoses come down into. There was no change when energized. When we plugged the other hose coming off the top of the T fitting, the problem got significantly worse and would barely curl the stick in, but turn the cab harder when trying to bring the arm in. More testing today This top hose off the valve block goes to the side of the main valve assembly. Not sure if that is the shuttle valve you were referring to. A diagram of this would be helpful. I am thinking by plugging off that hose, I might be cutting off pressure to the swing brake which is what makes it worse. Thanks Kobe Steel. Any more ideas are appreciated.
After several tests capping off different lines, only one hose seemed to cure the problem. I capped one of the two hoses that goes into the top of the block that connects all the joy stick hoses. There are 19 hoses on the block, but only two on top. All swing motion stopped bleeding when the arm is pulled in. I'm not really sure what the hose function is that I disconnected. Now I have another problem this has caused. When the arm is fully extended, the slew left or right will not move when the joystick is attempted to turn the cab. If I curl the arm in even one foot in, slew controls will operate. I tried downloading a picture of the hose position with no luck. It's the second hose on top of this manifold furthest from the door. I know this is probably confusing, but any help is appreciated. Trying to get info from Volvo isn't always easy. Thanks in advance
Hello Sir I will send some information for you to verify and hopefully I may be able to assist and provide support to help troubleshoot your problem. Kind regards
Upon further inspection, there are a few conflicting images that were received. The main image shows "G" with only one hose coming out of the top, we have two. In the main image it shows the hose on the end of the block "G" in tne upper of two ports which is what we have. In the exploded view "G" , hose marked G connects to the lower port. Not sure which would be correct. In exploded image of "G", we have a second hose attached to block G to the right of hose "H" where it shows an empty port. That hose goes to image "E" on the right end of the valve block where fitting 16 attaches.
Hi Kevman6 I have emailed you in regards to your notes above with some more information to try and help diagnose the issue best regards
In regards to the block "G" and hose G, which would be the correct location? Ours is in the upper port, however all hoses were banded and must have been taken apart before we bought the excavator. It's possible whoever was in there before looking for a problem put it back in the wrong place. We did pull the block G and inspected it and the balls for the valves, and all looked good. When capping the port where you requested, everything function normally as it should. I am going to pull the block "G" again and take a closer look.
I will do some research into that and come back to you. Try and do the testing if you can as its easy to skip over the problem, especially if your testing without using pressure testing gauges on the lines. Kinds regards
We do have the gauges for testing if we can get the specifics on which port and it's expected pressure. As of right now, if we cap hose" "B" highlighted in the main image, the problem is cured. Also if we cap the port where you requested , before the "T", the problem is corrected.
And I should say, where there should be no pressure.
Nice work !, going by your description above I believe you have isolated fault to the shuttle block (without the use of diagrams or workshop manuals). I found a hydraulic schematic online of a 240B model which I think has an identical layout to yours. If you look at the circuit diagram attachment you will see the shuttle block assembly(18) and pilot port block (17). I had asked you to cap and plug port Ai3 (arm in signal) which resolved the issue and you had mentioned that you had plugged hose connection SW1 ("B") and this test also resolved the issue. This means the shuttle valve above port SH1 is faulty and is allowing Ai3 ( arm in ) pilot pressure to bypass to ports SW1 (swing brake signal) and to Pa1 (arm in speed control ). For the parts diagram conflict, the hose layout should be going to the top and not the bottom, see attachment "hose correction" if you need any further help or If you would like to do more testing with gauges let me know and I can point out the ports and what the pressure should be approximately when a certain function is used. Kind regards
Is there any listing for that shuttle valve? From what I can tell, Volvo only shows the entire block listed as Valve 14544046 for $2K . Would be nice to try the shuttle valve and ball first. Or if there is a source of used hydraulic parts that might have the block.
Most likely Volvo will not have a breakdown for the block and $2K is very expensive for what it is unless they are also selling it with all the fittings as well?. Unless you can find a used one from a wrecked machine then the only other alternative would be to plumb in a shuttle valve externally. If there is enough room and length from the existing hoses then you could possibly get away with an external shuttle block connected to the existing block for well under $1k I would think. if you want any help for how this could be done , let me know and I will try and and draw some diagrams for you. Kind regards
All of the pilot circuits drain to tank through the RCV, So the only way this would work is if the plunger in the RCV for the swing function were not returning fully and blocking the circuit from draining to tank. The shuttle block is very simple. It is just a series of balls that seat against the fittings screwed into the block. Very easy to disassemble and inspect. The important thing is to ensure it is assembled and hoses are connected correctly. I have never seen one faulty before. I would advise against capping any lines connected to a servo cap on the MCV. It can cause unexpected and uncontrollable movement of the machine with a way to stop the movement.
Ben, I have capped the slew right and left hoses at the joysticks, one joystick at a time. When bringing the arm in, the cab still moved to the left. This I think would eliminate any leakage in the RCV (Remote Control Valve) unless it happens in the manifold assy where all the control hoses come down to. I was thinking this was only a pass through function. Correct me if there is a way it could be the problem Thanks
The RCV's are the drain to tank so if you cap the hose you are not allowing the circuit to drain. This will allow it to build pressure and activate a function. The hoses must be connected to tank or left open to atmosphere. I have witnessed this happen when someone capped the servo lines. Even if the shuttle were allowing the pilot signal from arm in to bleed over to the swing circuit it should only go to tank via the RCV which drains that circuit to tank.
Are you thinking that I tested it wrong, and it may not be the shuttle block that's the problem? I would hate to through a $2K part at it and find I didn"t fix anything because I tested it wrong.
Try putting a low pressure test gauge in-line for the hose connection sw to sw1 ( see the diagram I had posted to you earlier) Read the pressure in this line when doing the arm in function. I would think that if you have a 5 bar or higher pressure reading then this may cause the slew function to activate via its swing brake shuttle valve, Their should not be any pressure building up when you activate the Arm in function on this line. Kind regards
I will give that a test Thanks for the help.