Hello, Looking for any suggestions as where to start with this one. As above its a wheeled 130-6 from what I can see the same as the PC130-6 machine less the tracks. Machine runs well ex railway, 4600 hrs, no other faults found. Currently battling with an intermittent issue thats now regular.. All functions working except for the boom lift, you can here it auto rev when you move the controls for it, doesn't bog engine down, just doesn't lift. Then you can switch it off on 6-8 times and suddenly its working fine, then restart and its gone bad again, very random. I am thinking along the lines of bad solenoid/ low pressure on lift circuit, but have no experience with these so could be completely wrong
The last sentence in your post tells me that you don't have a service manual for the machine. Those machines are very rare in the States so finding anyone with any experience on them is going to be the needle in the haystack kind of find. I can only guess that you have a problem moving the boom raise spool and that something might be stuck in it preventing it from moving. I would suspect that the pilot operating system in that machine is hydraulic given the Dash number in the model name but that might not be the case. Komatsu in that time frame did produce computer controlled systems on certain models in those days. Do you have a parts book?
I do have a shop manual if anyone is needing it and have tried to follow it through. It has suggested either defective PPC valve or defective control valve spool as you have. My reason for thinking it was electrical is once you restart the machine it can start working again and is fine for hours, it doesn't happen again whilst the machine is running, only when its turned off and restarted. if this was a stuck valve would it not be constant, showing no sign of working consistently? I have just recently managed to burst a fairly new pipe to the quick hitch whilst just travelling the machine around. This is on the constant pressure side of the hitch. Got me thinking if it could be related? would over pressure cause this symptom and prevent lifting if the relief valve was faulty. Hopefully somebody out there has had similar issues, appreciate this isn't a common machine, though it is nearly the same as a tracked machine (PC130-6) with a different undercarriage so maybe transferrable knowledge
You have missed my point. We need to know if the pilot system, what your book is calling the PPC valve, is hydraulically controlled or electrically controlled. Just because you start and stop the engine and it works at times doesn't tell us anything. If you have the book you should have a hydraulic and electrical schematic of the system and you can logically figure out what your system is.
it is hydraulically controlled.
Super, if the problem is only affecting the boom circuit, you only have two areas to check. I would figure out which spool controls the boom. After removing the reservoir cap and making sure the implements are resting on the ground with no pressure on the boom cylinder, I would remove one end cap, it will have a small hose going to it, and make sure the spool moves freely. Inside the end cap will be a spring and probably some metal rings. I should back up and start at some other easy items to check. The first would be to remove the return filter and check it for any bits like cylinder packing or any types of metal.
Good day Simon May I suggest the following proceedure when the fault is active can you raise the undercarriage using the boom cylinder in that way we can establish if the fault is both negative and or positive please note a boom will free fall so the fault in that direction may not be immediatly obviouse - onece that is done we can move on to checking pilot pressure at the spool, we do not have a circuit diagram for your machine but if you hang one on the web we will try to help some more. Kind regards Uffex
it appears to be the gadgets the railways had installed on it in the form of load sensing devices. I was aware some of the sensors where getting damp inside but hadn’t factored in that a small separate valve block and solenoid was linked to these and wasn’t communicating correctly, Its was hidden behind the main control valve and piped to intercept the return line from the boom controls, I pulled the DIN connector off the solenoid and away it went! I may clean these load sensors or disable if this doesn't effect something else. Thanks for all the suggestions