Hi All, Above mentioned Kobelco (series 6, my 2000, serial LL08-03036) has bit of a strange problem. Hydraulic breaker is slow operating unless you activate arm open or arm close command, then it speeds up, but arm wants to move as well of course. Operator mentioned that it started happening all of a sudden, and no other problems are reported. Does anybody have hydraulic diagram for this machine, service manual, or maybe at least pressure settings. I can not figure out what arm and breaker are sharnig without a diagram. Or maybe someone has an idea what may be causing the problem? Thanks!!!
Also, what is this valve on the photo with wires sticking out?
Hammer circuit and arm circuit are both run off p2 pump. You say no other functions are affected only hammer if so I would first check the hammer circuit low pressure sensor. It's should be located under the cab wire tag se-11. To check you can swap it with one of the travel low pressure sensors they are marked se-9 and 10, another way to check it is with machine in auto idle activing the hammer pedal should cause the rpm to increase, if rpm does not increase the sensor is not sending a signal to controller
Thanks for the advice!!! I was told by the operator thet no other problems are noticed. i gave it a quick test, and couldn't feel any problems apart from brekaer being slow. I'll checj the wiring and try swapping. Do you know what is this valve in the picture? Thanx again!!!
I can't answer your question about your problem, but on a 250 dash 6 with a breaker fitted, you better remove that pump conflux switch on the console and disconnect the plug coupling on the back side of the switch. If an operator inadvertently flips that switch it will destroy your breaker. I learned that lesson the hard way.
Thanks for the advice. What's the purpose of this conflux anyway?
Ahh Ok, I think I've seen this on older CASE, but I don't recall seeing it on other manufacturers models. May be just my lack of experience. Also, can anyone help me with this valve that I took picture of? Customer rang me today about it again. He seems to be fixated somehow that this valve is causing issues, even tough it has been like this for a while apparently. Thanks!!!
We are going to need a wider picture of it to see where the big pipes go
When my hammer slows down it's because one of the hoses is coming loose at the hyd. coupler. I don't usually see any change when operating another function but I suppose it's possible that by opening the crowd valve that you are allowing more return oil to get back to tank than if only going through a semi-restricted return line. Is the hyd oil hotter than normal when running the hammer?
Kobelco Ireland answered that question in his post after that. Conflux basically combines output of both pumps to the auxiliary circuit, what would be, just to pick a random number, 50 gpm normally going to the breaker would now be 100 gpm with combined flow. If I recall correctly, and it's been years since I've worked on a dash 6 machine, seems I recall you can select "breaker mode" on the panel for operation, which prevents pump conflux when that mode is selected. But the problem is, the operator has to select breaker mode on each start up on the dash 6, you can't program the panel to default breaker mode on start up. So if an operator starts the machine and does not select breaker mode, then hits that switch, it's game over for that breaker. Kobelco fixed that problem with the dash 9 allowing you to program the panel to default to breaker mode on start up. But on the dash 6, if you're running a breaker, disable that pump conflux switch.
Hi Willie you can set all kobelco sk - 6 and upwards models and all kobelco sr-1 upwards models to default to which ever mode you need on start up. Depending on model and year some are done through the buttons on the dash and other by opening the controller to manually move a switch inside of it. Also most but not all of those older models had secret screens where you could adjust lots of settings, including boom up speed, arm out speed, throttle sensitivity to lever input, you could adjust weather you wanted more power in the tracks or upper functions when in straight travel etc.
This function (single pump flow or double pumps flow) is only available on SK dash 8 model, SK dash 6 model does not have this function!! Model SK dash 6 can set A or M working MODE at start up only, we can't set the machine in B MODE (Breaker Mode) at start up.
I have seen European spec and imported models back as far as - 6 with factory fitted aux circuits that have the two pump flow fitted. They are rare tho. I am only going from memery here but I am sure if you use the two left pins on jp1 you will get breaker mode. But like I said that's only my memory
Alright, I will check with JP1 tomorrow (I really haven't tried it!! ) . Anyway, I don't think the trouble of this machine due to 01 or 02 pumps flow reason!! I think the cause of this error as described is the failure to cut off P2 bypass.
I have a question. You report that the breaker slows down, and we suspect P2 pump may be backing off output, but no other problems were reported by the operator. My question, at the moment that the breaker slows down, will the machine still track strong with both tracks? Or is one track weaker than the other? Just throwing ideas out there.
Great info everyone!!!! Oasis of experience here I can see!!!! LACHAU, makes sense what you are saying, I'll check that for sure!!! Willie, I didn't try that. Bit hard to track and break at the same time. But I will try. i was dragged away from this machine with more urgent jobs, but next 2-3 days and I'll be back onto it.
Well, I wasn't suggesting to use breaker and track at the same time. Rather, when the breaker slows down, stop the breaker and immediately track the machine, see if one track is strong and the other is weak as the tracks are independent, one track fed by P1 the other by P2, if one track is weak that kind of confirms you have a problem with a pump and likely P2 as it feeds the breaker
I think it is not necessary to perform this check. Reason: the operator reported that the breaker returned to normal operation ( it speeds up ) when the operator combined the lever in (or) out ARM operation (as noted above).
Thanks all for grat and in detail explanations!!! Breaker broke 2 out of 4 main bolts holding it together (don't know what they are called) so off it went for a repair. I'll do more tests when it comes back.
This machine keeps piling up problems. Breaker came back from repair. 20 minutes into work, it blew out low pressure sensor on the pump. Pissed out 90 liters of oil before operator noticed fault on the screen flashing.
Which sensor went, negative control? On pump2?
From what I was described it was sensor mounted on top. I didn't take it off, owner took it off and bought it to me. i'll have a look which one as I'll be passing by there later today or tomorrow.
Sensor replaced was low pressure sensor for P1 pump. I also found that pilot pressure measured at the pump was 55BAR. Looks like someone was eyeballing stuff when adjusting. I'm getting contradictory info on what pressures should be. Some documents say 24 BAR, some 32-36 BAR. Does anybody have a document specific for this model that shows adjustment and measurement points for all pressures? I would like to check them all. Model SK250 NLC 6 MY: 2000 Serial: LL08-03036
Pilot pressure at high rpm should be around 40 bar
Ok, so it is around 50 BAR. Is there a diagram maybe where the measuring points are located on the pump? I had a look on the pump it self, but I couldn't see any markings.
Great! Thanks for the info! I'll readjust and check again. Heavy rain these days, all work stopped.
Just to to be clear on something here. I was looking at this document earlier, and adjustment of pilot is around 24 BAR on this. But it also metiones flow. What am I looking at wrong here? document doesn't outline for what model exactly this valve is. Is it that some models have 24 BAR pilot pressure, or it gets reduced in this case for the valve? It states Pilot pressure max 24 BAR (or so), but at certain flow?