Kobelco sk160lc-6e hydraulic issues

[Bptrucking2017]

Good afternoon all, been on this site a long time hanging in the background reading and learning about others equipment issues. But this is my first issue and post my self.

I have a kobelco sk160lc-6e ser # YM03-u1062. I was working on a job yesterday when it seemed like the bucket curl was a little weak, not crazy weak but just didn’t have its usual strength. I then noticed that I lost my ability to track/travel and run any of the other functions requiring hydro pressure (boom up, house rotation, stick out, bucket curl) but the control valve is responding to input from the control sticks (boom will lower and stick will come in via gravity)

I also figured out this morning while working the machine that I can get pressure for the house swing if I depress only the right travel pedal but not if the left pedal or both pedals are depressed. If the left travel pedal is depressed the boom will function under power as it should but will not get pressure if the right pedal or both pedals are depressed.

I’m hoping this is not being caused by the main pump and hopefully it’s something easier to figure out. I’m not expert with hydraulics but am very mechanical so hopefully with a little help pointing me in the right direction I can get this sorted out and fixed with your guys help.

Thanks in advance Brett

 

[Kyle Helmke]

it sounds like it may be an issue with the pilot pressure sensors.
1. if you operate boom swing or bucket without a travel pedal what happens.
2. when you put the machine in independent travel what does it do.
3. what do the nega-con sensors read in the back screens
4. what do your pump psv's do when you activate a function.

 

[LACHAU]

Good afternoon all, been on this site a long time hanging in the background reading and learning about others equipment issues. But this is my first issue and post my self.

I have a kobelco sk160lc-6e ser # YM03-u1062. I was working on a job yesterday when it seemed like the bucket curl was a little weak, not crazy weak but just didn’t have its usual strength. I then noticed that I lost my ability to track/travel and run any of the other functions requiring hydro pressure (boom up, house rotation, stick out, bucket curl) but the control valve is responding to input from the control sticks (boom will lower and stick will come in via gravity)

I also figured out this morning while working the machine that I can get pressure for the house swing if I depress only the right travel pedal but not if the left pedal or both pedals are depressed. If the left travel pedal is depressed the boom will function under power as it should but will not get pressure if the right pedal or both pedals are depressed.

I’m hoping this is not being caused by the main pump and hopefully it’s something easier to figure out. I’m not expert with hydraulics but am very mechanical so hopefully with a little help pointing me in the right direction I can get this sorted out and fixed with your guys help.

Thanks in advance Brett

I guess you just repaired something to your machine, right?

This error is caused by you incorrectly installing the control lines of 2 main pumps!
Try swapping the wires connected to the two proportional solenoid valves (PSV-P1 & PSV-P2) on the main pumps.

 

[LACHAU]

 

[Bptrucking2017]

it sounds like it may be an issue with the pilot pressure sensors.
1. if you operate boom swing or bucket without a travel pedal what happens.
2. when you put the machine in independent travel what does it do.
3. what do the nega-con sensors read in the back screens
4. what do your pump psv's do when you activate a function.

Swing is usually fine if pumps are working correctly, bucket dump (cylinder retract) seems normal but bucket curl ( cylinder extend) the oil sounds restricted and is rather slow probably close to 1/2 speed of bucket dump (cylinder retract) both dig and dump show 435psi and 4.8v on the pressure sensors on screen 11 in the monitor.

I’ve been working with a local kobelco mechanic over the phone and we found a p2 pressure sensor that was reading off. Fixed that also found 2 wires on one of the pump proportional control valve but now I’m getting random pump loading. It’s always in pump 2 it will even do it sometimes when the arm rest lock out is raised (locking all function out) lock is killing all machine functions except for pump loading. Weird thing is it doesn’t always do it. Sometimes it loads while operating the machine also. I feel if I could figure out the pump loading issue ide probably have this figured out lol. The mechanic I’ve been talking to is thinking electrical gremlin. I started pulling the pump harness Spartans go to where it passes by the main control valve and decide to stop. I don’t see anything unusual on inspection, nothing rubbing or pinched. Thinking I should check the harness where it comes in to the cab next Incase something chewed some wires?? One other odd thing is when the lock out/arm rear is thrown down or up both travel pedals jump ever so slightly. They rock forward when the arm rest is lowered and rock backward when it’s raised.

 

[Bptrucking2017]

I guess you just repaired something to your machine, right?

This error is caused by you incorrectly installing the control lines of 2 main pumps!
Try swapping the wires connected to the two proportional solenoid valves (PSV-P1 & PSV-P2) on the main pumps.

I can try switching them but this started acting up during the work day, machine was working perfectly for most of the day when I noticed it acting up. And all while running and working it. Wasn’t like one of those machine worked fine all morning, parked it and shut it down for lunch and came back and it was acting up. It was just like someone flipped a switch.

 

[Bptrucking2017]

Also not sure if this is note worthy or not but #23 proportional valve for recirculation is reading 413psi on the first line and 397-400psi on second line with machine running and 413psi top line and 390-396psi with the machine engine off. Is that we’re that’s supposed to be or is that maybe part of my problem?

 

[Bptrucking2017]

Also noticing that the stick in can be very slow but stick out is normal. Stick just kinda falls with gravity most of the way in. But if I curl the bucket at the same time then the stick comes in at full power and speed. Almost like I have something stuck in a multi function control?? Just weird seems like it any function gets week/ no power at all now if I pick another function to do with it, it will instantly receive pump pressure and work properly, till the second function is stopped then the first function goes back to slow/no power

 

[Kyle Helmke]

do you have independent travel or heavy lift on?
when the pump loads up you need to look at the back screens and see what is turning the pump on
check the wires where they go through the metal clips under the pump or right at the plugs

 

[Bptrucking2017]

I

do you have independent travel or heavy lift on?
when the pump loads up you need to look at the back screens and see what is turning the pump on
check the wires where they go through the metal clips under the pump or right at the plugs

I do not have the independent travel or heavy lift switch on sadly. There is nothing I can find in the back screens that is causing the pump loading, the readings for boom, bucket, arm, travel and rotation are all normal. Only number that seems off is the arm recirculation reading around 400psi on both lines of screen. Still have more of the harness to check but so far nothing to report on anything new sadly. Starting to wonder if I have a failing pump control computer with how many different issues i seem to be having all at the same time

 

[Bptrucking2017]

Ended up swapping the a-6 arm recirculation proportional control solenoid with a-4 straight travel proportional solenoid and used the machine for about 1/2 hr, things are vastly improved with machine function. Currently very hard to track machine as when trying to make small directional adjustments it’s very jumpy now so I have a new proportional solenoid on order and will put the new one back to arm recirculation and the one I swapped from straight travel back to its proper home (being arm recirculation is used more often) and hopefully things should be back to normal