Komatsu PC230 caterpillars (tracks) problem

This topic contains 9 replies and was last updated by sinisa 8 years 10 months ago
December 7th, 2012 5:29pm
when I move excavator the tracks suddenly slows down and the pumps in that moment make strange sound, after I re-ignite command for move they work fine, and after few seconds they start to stop or stop-start-stop-start but with kicks. The pumps in that moment sound like they have a problem with sucking or pushing oil out (my impression) Well this problem is particularity noticeable in the morning when the machine is cold, after 1h of work when

everything is hot the problem is a little milder.

Could it be an electrical problem?

We have the similar problem with other excavator, the tracks slow down or almost stop. And the problem was some electrical relay located on DC excavator alternator!

December 7th, 2012 7:50pm
It does sound like your pumps may be cavitating. As they are piston pumps, this will cause serious problems quickly. This could be caused by high viscosity oils or the charge pump is not functioning well enough.

You will have a test port on the charge pump line to check pressures. If your books tell you that pressures are in line, you will have to continue looking and maybe do flow tests on the charge pumps.

On newer equipment, these pressures and related are monitored by the computer. A scan test on the system may make it easier to pinpoint.
December 10th, 2012 12:14am
I would check the pilot pressures as it may be problems with insufficient pilot pressures which translates into problems with the actual function that is requested.Also the pilot system may have a valve which is ignited when you actuate the safety on the left armrest to operate.
December 10th, 2012 10:20pm
Is it possible that the valve on the left armrest to operate is defect. Is the failure of this valve manifested like in my case?
December 15th, 2012 5:22pm
I would expect all hydraulic functions to be affected if the armrest hydraulic lockout lever switch was malfunctioning. What viscosity of hydraulic oil are you using? I agree with Will and Jim. I would definitely closely inspect your hydraulic suction lines between the hydraulic tank and the pump for leaks or poor connections that could allow air into the system. Checking pilot pressure is another good idea. If you have an infrared thermometer available, what is the temperature of your travel motors when problem occurs? When machine is cold, are the travel motors substantially warmer than the rest of the hydraulic system after activating the travel motors for a few minutes? Perhaps, you could lift one track off the ground with your stick, activate the travel motor for the raised track, and see if the problem occurs for one side and not the other. Have you noticed problems with any other hydraulic functions?
December 15th, 2012 5:26pm
I forgot to mention that Cat excavators have two main implement pumps and that the hydraulic functions are divided between the two pumps. For example, your right track might be proved flow from the RH pump while the LH track is provided flow from the LH pump, and straight travel might have both pumps providing flow to both tracks. Komatsu might be set up this way also which could help you in isolating the problem.
December 16th, 2012 8:28am
I was just reflecting on your problem and had a brain f-rt that should also be checked out.

Komatsu, John deere and others have a pressurized hydraulic tank system, where a pressure head over the oil forces more oil to the oil intake system. If there was an air leak from the tank, or for whatever reason the tractor was not able to pressurize the tank, would allow or cause the system to cavitate.

Just something that can be easily checked.
December 16th, 2012 10:08pm
Ok, we resolve the problem. The technician came and he first check oil level he found that oil is missing. Somebody stole 16 gallons of hydraulic oil over night from hydraulic oil tank. Its our fault that we did not check first obvious thing. I think the technician had a good laugh :unsure:
December 16th, 2012 10:10pm
Thanks to all of your for help :)
December 17th, 2012 1:14am
Thank you for letting us know. Too often we never hear back from people to let us know the problem was fixed.

I understand how it might be embarrassing to acknowledge that such a simple thing wasn't caught, but none of us answering your problem asked either.

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