Kobelco SK200 LC

[Ncjetskier]

OOPS, my screw up - I think he was questioning how many splines on the shaft. I took my phone and jammed it into the pump area and took pictures. I did find a stamp (not a plate) with what appears to be K3v112 with some letters underneath.

The problem I am running into - is that people that travel and work on equipment - show up, tell me what they think and leave. I realize this is a project machine - but I am willing to pay to have it fixed. It just seems like nobody has the time - and they may not. It is making me learn ALOT about the machine which is a good thing. I just don't know much about hydraulics or servo valves. I did go to U tube University to learn how the pump works so I do understand how the pistons ride on a plate that can be adjusted to increase the pressure. I will go back to U tube University and see if I can learn how to adjust the plate to increase or decrease the pressure.

On Saturday, I pulled the screen filter in the hydraulic tank after draining the fluid. The screen was a mess (probably never cleaned) and my hydraulic fluid was the color of coffee with cream added to it (moisture from sitting too long?) I cleaned the filter and replaced all the hydraulic fluid with new fluid. The screen did have metal shavings but they were steel as they stuck to a magnet but no brass shavings from the pump. The cleaned filter and new fluid did not make a difference.

Is there a high pressure test port to test the pump pressure? I did purchase a pressure gauge that goes up to 5000 psi. The last technician disconnected one of the wires going to a pressure valve (bottom left hand side of the pump) and it did not make a difference. He stated that my problem was not electrical - but he did not do any testing accept for removing the wire from the valve to see if it would make a difference.

I guess my next step would be to test the high pressure side of the pump with a gauge and learn how to adjust the pump plate.

 

[Kobelco ireland]

Update; I had a very skilled heavy equipment mechanic look at the machine. He stated that it appeared to be the pump based on how the machine was working and that ALL of the hydraulic functions were slow. He recommended a rebuilt pump.

Sounds like a part cannon to me.

 

[Kobelco ireland]

but he did not do any testing accept for removing the wire from the valve to see if it would make a difference.

so he disconnected one solenoid and condemned hydraulic pump.
We need to know the pump pressures because weather or not there is pressure will determine what direction you go with the repair. Post a few pictures of the pump and we can point out the test ports

 

[Ncjetskier]

Yes, you are correct. Disconnected one valve (high pressure valve?) and that was it. I am going to have to figure out (myself) how to test the high pressure side of the pump and how to adjust the pressure plate.

 

[Kobelco ireland]

The plates you are talking about are called swash plates, changing the angle of them changes flow rate not the pressure of the pump, pressure is set be adjusting the main relief valve which is located on the main control valve(valve chest). Also what you call the high pressure valve is the pump solenoid. Post pictures of the pump and we will point out the different parts and where to attach your gauges etc.

 

[Ncjetskier]

Here are pictures of side of the pump

 

[Ncjetskier]

Another pic

 

[Ncjetskier]

One last one

 

[Ncjetskier]

Update: Brought the pump to get rebuilt (company specializes rebuilding pumps and has been doing it for 50 years). They called and stated the pump has normal wear (swash plate and piston edges) and can use a rebuild. However, based on what they saw, the pump is not the cause for the slow hydraulics. Having an experienced person pull the two main valves / solenoids.

 

[Kyle Helmke]

Check your signal wire from your alternator if it does not switch from a power to a ground the machine will not shut down with the key. This can also cause issues with not starting with the key as it thinks the engine is already running

 

[Kyle Helmke]

Did you check your pilot pressure that can cause slow hydraulics. Are all functions slow or just some of them? Does the machine track normally

 

[Ncjetskier]

Yes, the pilot pressure was at 800 PSI, so I think we are good there. My plan is to put the rebuilt pump back in and then try to do pressure readings leaving the pump to try to see where the pressure drops. Not sure if this is the best way to track it down, but I am running out of options? Thanks!!

 

[Kobelco ireland]

Check to see if you have full main pump pressure with system held over relief. If you do have full pressure, you have a low flow problem. Are all functions slow or just some. How slow is the machine can you post up cycle time results

 

[Kyle Helmke]

If the machine has set for a long time I've seen the main reliefs rust up.

 

[Ncjetskier]

All functions are slow (boom, bucket, travel and swing). Travels about 1/2 mile an hour if this gives you and idea. The system is a dual main valve system (?). A mechanic (mechanic #3) pulled the valves and stated that he did not see anything obviously screwed up. His plan is to put the rebuilt pump back in, do a high pressure reading at the pump then do pressure readings at different points as you leave the pump to see what point the pressure drops.

Pump will be ready for pickup this Friday and they are replacing the valve on the pump.

 

[BigWrench55]

Pressure is power and speed is flow. You will get good pressure readings if the pump is good and the relief valve is good and still have slow functions. If the pump isn't stroking up when a function is activated then you will get slow functions. I'm not sure how your pump flow is regulated. You will need that information from one of the other guys on here to troubleshoot that. Right now I believe that your pumps are not stroking up and your pumps don't really know that you are calling on a function.

 

[Ncjetskier]

Bigwrench - thank you that explains a lot. I did replace the governor motor and did not have any luck with the "Program A" to get the CPU to talk to the gov motor. I am able to increase the RPMs using the dial in the cab. Can I push the "release:" lever to bypass the cpu? Even if I have the RPMs high, everything is still sluggish.

The pump rebuilding company did not put the original pump on the dyno when it was brought in. They just told me that "the pump had normal wear and tear but nothing out of the ordinary". They are putting the rebuilt pump on the dyno tomorrow and will provide a readout when I pick it up.

 

[Kyle Helmke]

If you are using the hydraulic override that is why your functions are slow the machine controller is what controls your pump psv's. That is for emergency to get the machine to a safe location. What happens when you try to do the A adjustment, does it fail or just not start one

 

[Ncjetskier]

The first time it failed - symbol flashed a couple of times and stopped. Afterwards it will not start the process.
The special plug has three connectors. I only used the two connectors that connected to the one wire coming out of the cpu. (disconnect the plug, plug the special wire harness into one end, then connect the other end of the special wire harness to the other end of the cpu wire). The third connector does not connect to anything. Is that correct?

Up to this point, I have kept the machine in KSS and have not used the override - but was considering switching. Thanks for the information above, I will keep it in KSS mode.

Thanks for the help.

 

[Kyle Helmke]

Are you talking about a harness with a push button or harness for programming. It's been a long time but if I remember right you have to start the process with no error codes then hit the button to move through the steps