Any guess? I have no lube chart for a reference, and tech service won't answer the phone of course. Dealer parts dept says it has one....pt number 20Y-62-51961........service manager there says it may not even have one. Does anyone know for sure? .....cause my dealer here has no clue!!
I've never seen a pilot filter in any Komatsu excavator. I would be interested if there was a drawing showing where one would look for it. In my experience, a Komatsu dealer service manager is a pencil pusher only. Try to get a hold of someone on a field truck or a knowledgable parts person. Parts person might have access to factory information that might define if and where one would find it.
John's right, Komatsu has a thing against filters. They use main pump discharge through a "self-pressure-reducing" valve to generate pilot oil. That's why you don't see a pilot pump piggybacked off the 2 main pumps. What do you got going on?
They didn’t use a pilot filter even when they did have a pilot pump.
Well, the operator is telling me the joysticks control are blanking out at times. I asked if it was all the controls and he confirmed even the tracks wont operate. I know they lack alot in maintenance so I wanted to check filters for the pilot system first...couldn't find one! LOL I have not seen the machine do this yet so I haven't been able to troubleshoot any probable issue. So at this point I'm not sure what's going on since it works fine while Im there or operating it myself. I'm thinking it could be electrical, possibly the wiring at V01 or the coil itself. Guess I'll have to wait until it quits working or fails completely.
Pilot safety solenoid is probably getting weak. No filter though. There is an inlet screen to catch trash, but that's it. It wouldn't cause intermittent. Good luck.
Were there any alarms of fault codes mentioned? I would probably pull the plates under the cab and start looking at the wiring and connections. I don't know if the electronics in a Dash 7 would pick up a disconnection or over current situation in a solenoid. You might check pilot pressure. I have heard of a couple of issues happening with the pilot reducing valve. Those issues were too much pressure though.
No mention of alarms or fault codes. It seems the operator quit his job yesterday on unrelated issues here.........so now I will have to deal with a new one, providing the issue continues.
Ghost problems maybe. I've had plenty of Friday issues that turned out to be operators not wanting to work on the weekend.
Well, it looks like the pilot system is still blanking out at times. I'm going to go there this morning and see if there are any codes logged, as the operator is saying nothing is coming up on the monitor. Keep in mind I haven't seen this machine act up yet, its a ghost that only seems to appear for a minute or 2...then disappears. I am assuming in the service mode I can select live monitoring of the pilot pressure , if so......Im going to leave it displayed so if it acts up again the operator can tell me if the pressure is dropping or falling out completely. I have a spare solenoid valve so I am going to switch it out while I am there.......at least I can eliminate that as a cause. I don't figure it will hurt since the machine has 17000 hours on it! Right now I don't know if its electrical or hydraulic. I hate crap like this but its not my first rodeo. The operator did tell me that when it did this a few days ago, it was off for 7.5 minutes before it came alive again. He said the only thing that worked was the bucket curl which makes no sense to me. I'm wondering also if the manipulators including the travel valve have those inlet screens for the pilot pressure lines at each valve?
I might take an oil sample while you are there. The only place that I recall has screens in a Komatsu were in the pumps. You might pull the return filter and look it over close. A look at the strainer might not be a bad idea as well. Is the pump in this machine original? It might be just time for a refresh. The monitor mode I believe does have the ability to watch the pilot pressure live. The monitor will go back to the standard mode every time you shut off the key. I do seem to remember issues with compensators slowing down or even stopping things on the Dash 6 line. Maybe you can watch LS pressure as well.
I made it there yesterday morning. I pulled up the service mode and checked for any codes related to the pilot controls, nothing on electrical or mechanical. I went into monitoring and scrolled through the listings and didn't find a specific line item for pilot pressure. What I did find is what I think may be the pilot on/off solenoid electrical signal current (it was listed as PC -something, I should have wrote it down but didn't). I left it on the live view for the operator to observe while operating the machine. I did change out the solenoid valve at V01 to eliminate the possibility of the coil being a issue. My intent was, if the machine did lose the pilot controls again, for the operator to check that line and see if the electrical current had changed in any way. About 2 hours later he called and said that the pilot controls had died again, but come back on within 30 seconds of him calling me . He said the current was @ 615-625 (don't have any parameters). He didn't get to go through everything I wanted him to do since the pilot operation returned. It didn't act up the rest of the day. The ghost made a very brief appearance and POOF....GONE AGAIN! Now my question. I'm not sure what the issue is as of yet, whether its electrical or a hydraulic problem. Would Komatsu's ET show a bigger scope of the machine operations that I can see/ monitor in the service mode? I am assuming that maybe they can monitor pilot pressure? I am trying to decide if I need to have the dealer hook up to this thing but I don't want to have them out if they are just going to see the same exact thing I am. At this point, unless it fails long enough for me to actually do some troubleshooting, there isn't alot more I can do. I could install a hose in the main pilot line and see if the pressure dies off but if Komatsu ET can monitor that, I may wait. What do you Komatsu experts think?
An electrical problem would have set a code. In the past there was a top secret connection for a laptop and software but I was long gone from the dealer when the Dash 7 line hit the US shores. The Komatsu thought process was to always put the diagnostics in the machine and not have to use an outside sourced piece of hardware in order to repair their machines. I would be very surprised if they made any changes to that design strategy. At this point I would have a conversation with the owners of the machine about letting the problem manifest until something concrete happens. I might also clue them in on a possible operator issue. No use spending any more of their money on ghosts.
Im wondering if the safety switch or its wiring are compromised. It would think you just dropped the lever, not something to log a code.
It is a possibility that I had thought about. I didn't figure it would set a code for that either being it is more of an off/on switch. I was thinking I might see something in the solenoid electrical signal fading out when the problem arises. I haven't ruled that out!