Volvo EC240CL hydraulic problem Need some help

[kevman6]

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

 

[funwithfuel]

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.

 

[kevman6]

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.

 

[funwithfuel]

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.

 

[kevman6]

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?

 

[sfrs4]

track or slew ?

 

[sfrs4]

try this.

 

[kevman6]

Sorry, just the body is turning left, not the track driving it.

 

[kevman6]

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

 

[kevman6]

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?

 

[funwithfuel]

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.