I have a 2003 kobelco sk70sr that is having hydraulic issues. I just replaced the pump because the old one went out. Put the new pump on and it worked great for about 2 hours one day. Went out the next day and 15 minutes into working it started killing the engine. Replaced all the fuel filters and went through the fuel system. Have since changed all hydraulic filters and fluid. Pull valve body apart cleaning and looking for anything broken or scored. I have 4700psi from main pump and 500 psi on pilot valves. The issue is that whenever you deadhead or load up any function it bogs motor and wants to stall it out. Please any help will be greatly appreciated
Good day The pump needs to reduce the flow under higher pressure, if the engine condition is good the pump swashing back comes into question. Question why was the pump replaced? and what precautions or measures were taken? Kind regards Uffex
So the old pump had quit building pressure. I agree that the swash plate is not adjusting as needed. But I had the old pump rebuilt and installed it and it’s doing the exact same thing
Good day I suggest you make certain that the engine is not guilty before going hydraulic. If the engine is good no smoke - good fuel equipment ect, then check the pump regulation. If you have a manual it should give instructions or you can appeal for a manual here on the forum. Kind regards Uffex
We have ruled out engine. I have a manual on the machine and it does not say much about the regulator. Would adjusting the regulator be a potential fix to this problem?
Good day Dan I would suggest adjustment would fix the issue it may cover it up with more potentinal issues. Youm must establish root cause to come up with a fix. I will check to see if I can find the correct information , mean while a fellow posting here on the forum his name escapes me at the moment is very knowledgble with the Kobelco product. Kind regards Uffex
Good day Dan The guy I was thinking of is Lachau, for me to help some more can you please post a photo of the pump label. Kind regards Uffex
I can not find a Id plate but I can get the part number. So today I had the gauges on it and it would go to 5000 psi and with a small adjustment I got it to reduce down to 3000 psi when it would dead head but the engine would still big down and black smoke a lot. Wouldn’t stall but definitely bogging very bad
Good day Dan As to the best of my information, you have a single valve controlling the point that the swash and flow reducing piston is activated. Either the valve is not operating correctly or the piston cannot move the full stroke. The pump I guess is a Kayaba the label is on the side. With that information I have the possible source of information to help. Kind regards Uffex
I know it’s a Kawasaki pump. That much I do know
Good day Dan I would suspect a pump internal fault with the regulation, if you have a local dealer take the pump in to be bench tested. Please do not overlook precautions - take care of the fluid - tank - filters and bleed the pump when commisioning. Kind regards Uffex
Correct. When you adjust the regulator to reduce the load on the main pump, the engine of the machine will no longer be overloaded Please try adjusting according to instructions (2) and (3) of the attached image. Note that you should loosen the adjusting screws, not tighten them further.
Yes I am replying to an 18 month old thread. Hoping Lachau or someone else can help me. I have an SK70-SR1E SN UT02-04874 which we are coming down to determining that the pump needs to be replaced. Since this is expensive and time consuming I'd like to make sure I try everything else first Unfortunately the prior owner changed many settings on reliefs and even managed to lose a control screw for the pump. I have been able to find a screw assembly now so that I can make an attempt to calibrate the pump correctly. I have the same instructions as the post above from Lachau in my manual but no starting point. If anyone has access to a similar Kawasaki pump SK70 and could get pictures or showing thread counts on the three adjustments above it would give me a starting point.
What we had to do was set a gauge on the pump and dead head each cylinder one at a time and make adjustment while the cylinders were pressurized.
Thank you for thinking about this. I would think that deadheading while measuring pressure would only tell you what the main relief valve setting is. Maybe I'm not understanding. There are three settings, two on one control for horsepower control and input horsepower, 2 & 3 in the instructions. Setting 1 on the other control is for max flow. We are dealing with an issue that seems related to the compensation controls on the pump but until we have the pump settings sorted out we can't troubleshoot further.
While you’re dead heading them every adjustment will show on the gauge. You’ll have to watch gauges and rpms of engine to get them set as close to where they should be. What exactly is the pump doing?
I don't really know what the pump is doing. Puts out 4000 psi at main relief crack. When controls are engaged you feel and hear the pump output go up. Stick in, bucket dig, swing, and travel are all weird. Swing triggers pump after a moment of hesitation, then drops output and crawls around. Bucket dig very slow until last few degrees of travel. Stick in hangs like a plumb bob at vertical for a few seconds then takes off for the remaining foot or so of travel. Travel surges, takes off then whiplash drop, then leaps again, repeat. Better on two speed travel. In all cases the pressure output is dropping off. Main relief seems to be ok, max pressure changes when it is adjusted, internals look good. Have been replacing port reliefs that are damaged with no change to behavior. When operated with other controls that stroke the pump those controls work well. When a small resistance is provided to the functions the pump strokes and works well. Put tip of bucket in the sand a few inches and swing goes with nice power, stick in, drive, and bucket dig same thing. No weird noises from any part of the system. My best guess at this point is that some aspect of the pump compensation control system is not working correctly, either because of setting or a part failure internally. I did check springs in upper control and both seem fine. If I take it out and run it doing a regular digging project you rarely even notice the issue since most operations involve combined control inputs or resistance. Sorry for the long read, hoping the detail will save you having to ask for details.
Sent you message with my phone number
Swap p1 and p2 pump outputs and see if the fault moves to the other circuits that'll show if it's pump or not, only thing it could be really in that regard is if the lense plate or barrel are leaking off on that output of the lense plate as it's divided on these machines. If it doesn't move definitely in the control valve which is say is more likely, I'd make sure reliefs are good and then the overload, the straight travel valve, the p1 and p2 valves, and laid check, definitely sounds more like you are loosing flow somewhere, I'd operate those functions honestly and feel the control valve or thermal image for where the heat is is where you'll be loosing flow
I did try to swap the outputs, unfortunately this is a 20 year old short radius machine. Got them off the pump but they are so inflexible and have so little extra length that I was concerned the hoses would be damaged if I tried to force them that hard. No access to the main valve to swap there either. Function issues are on both sides of the valve/pump output. In my long post above I didn't specifically say that the opposing functions, stick up and bucket dump, do work well, which they do. Pulled spool from travel straight and it shows no signs of damage or debris. When dropped back in it is smooth and goes on its own.
Yeah main concern is it being bad on both functions once you take bucket into account, I still feel if possible it's the best bet, to force the hoses and see, otherwise I would check case drain leakage from pump and pump housing temperature for excessive heat generating from leakage.