Alright new here, and I'm grasping at straws. I have a Kobelco sk160LC-VI, but I can't locate a SN. The previous office had a kobelco mechanic who I can't get in contact with who was picking parts for the dynamic acera SN beginning ym02. So basically this is what was done. The machine has had the kawasaki pump rebuilt twice first time with used parts, lasted 1.5 years, probably 1500 hours or so, and most recently everything on the pump rebuilt because it was grenaded due to negligence and had brass throughout the whole system. So I cleaned the whole system multiple times over the past year. 900 or so hours after pump rebuild my stick boom start having problems as follows: The stick would drift in by itself like a bleed off when used the stick would drift in aggressively and prevent the motor from going to an idle I had track issues left and right intermittent. and RH swing was slow. and I had what felt like turbulence in a pilot line. The first solenoid on the block behind the cab was probably 160 degrees Everything hydraulic is slow I cracked lines and valves and cleaned everything out again, multiple times now. After doing some cleaning, at some point, I've regained proper tracking and swing. I do not have an idle down issue at the moment. And drift seemed to be gone. Pilot line seems to be turbulence free. But my top boom to stick will not retract. So i opened line multiple times for the retract and got air and maybe a few ounces of fluid. I went back to corresponding valves and did another cleaning and inspection and found nothing significant aside for my smaller beehive springs are slightly shrunken and loose so they have some wiggle as they float, but the larger springs are still 100%. Both sets of springs are 110 pounds of force at 2" compression. I pre-filled cylinder with fluid and tried to exercise and nothing. Putting my hand on the line up the boom it's almost as if theres absolutely no flow in the line. I was told by a kobelco mechanic that I probably have a bypass in the cylinder but I'm not getting any fluid flow from either side independently. So i looked at solenoids behind cab again by pilot lines. I have 2 types of solenoids. The ones labeled KDRDE5k are testing 17 ohms consistently. The KWE5k-31/G24DA50 are all testing 34 OHMS, aside for one which is 17 ohms. I bought a new 31/g24da50 and it ohmed at 34 brand new (MOTTROL aftermarket). So I'm not sure of what the resistance should be, I would assume 17, but I'm getting 34 from a brand new and all the others but 1, which is confusing me, and leading me on. I put the new kwe5k-31/g24DA50 into the first slot on the bank of the solenoid block behind cab. We had a slight cylinder drift out for 5 minutes when the cylinder was half extended, but it exercised out at a low idle. The machine ran great otherwise for the 30 minutes we had it running, the solenoid was normal fluid/pump temp. We curled everything in and left the machine on a level and came back the next morning, the top stick boom will not retract again, hydraulics over all were slow and labored trying to track out of the way. We have had water issues with the computer in the past where connections would get wet and we'd have idle down issues. This doesn't seem to be the case here as I've been dry. With the machine key on i have a psv p1 proto bypass code. I've switched the solenoids and plugs at separate instances, solenoids seem fine, the plugs only switched from p1 to p2. With key off I get a mechatron cont failure code, and I've traced wires but I'm not seeing anything. I feel my operator has neglected these codes and they've been here for a while as we've had them before and I think it came back to the plugs at the pump, which seem to be fine right now. TLDR; I can't retract the top cylinder, when i try to boom out more it sounds labored. I can't do two processes at the same time like I could before. Seems like reduced flow, but team works great again. It's almost as if the pilot isn't activating for flow to go to the cylinder. So any clues where I'm to look at this point? The pump solenoids are testing at 17 ohms. I never pinpointed what caused the tracking issue but that went away after i attacked the valves.
Good day That sounds like a classic case of contamination big job split it all down and clean out, there was a recent thread with an Hitachi similar faults. Kind regards Uffex
That's kind of we're I'm at still too. Thanks for the opinion. I'll try to find the Hitachi thread later. Update: I cracked the line at the cylinder and have flow and cylinder movement. I just got an o ring kit with everything for the machine. A lot of the installed o rings are almost fits and wrong thickness. Maybe i'm not air tight enough going up the boom. The boom broke and stretched the steel lines/ fittings 2 years ago. I'll see what's going on from there.
I think you should start way back at the pump first. You prob need to look up each pump on the LCD display and check out the pressures when on bypass at high engine rpm. They will be P1 & P2 Can’t remember how to get into it......... there’s quite a lot of info about the hyd system in that corner display. I have an SK170 and have just been thru the pump failure and resulting contamination thing.............. Feel for you. Sounds like your on top of most things, but start back at the pump and confirm things are up to spec there first and then follow the hyd system from there in order of function flow, till you end up back at the ram. There’s a valve somewhere that controls the dipper arm from charging back at you with a heavy load on when extended away from the machine. I don’t know where it is. Maybe there’s an issue there? I don’t know much else. Just a dumb farm boy here. Best of luck. I always run in Auto mode for the machine by the way. There’s no labouring then and better hyd’s. Have you tried Auto?
I ventured into the Valve stack looking for a problem after my pump failure. After looking at things in there I came to the conclusion metal will get thru there without getting caught up. SO AVOID THE VALVE STACK UNLESS absolutely necessary. Mine leaks everywhere now. Was spotless before hand. Not happy bout that.
What are you considering the valve stack? I assume where all the cartidge valves and spools are? I've been open and closed for about a year now, which was very much needed, and no leaks, as long as I use an appropriate o ring. I haven't gotten into the display yet. I side tracked for a komatsu pc220 that was recently rebuilt that I had to go back through and redo. After I got the motor smooth, 3 hours into running, I think I lost a pump but I'm not sure. So I'm splitting between both machines.
So I'm reading through posts, I am not an expert, just learning as I go and have enough common sense to be dangerous, and really just need someone to point at some things and say, that's what that is. So I came across mr kobelco's post in his topic and what I assumed was purely air intrusion, is actually what he described and makes much more sense. The stick reaching 90 degrees then swinging causing cavitation. Before I get redefine my problems again. I still have mechatron failure, which I haven't traced yet. And a propo valve bypass, I forget if it's p1 or p2. The valves were fine when interchanged on pump, but electrically the code follows the connector. So, still have tracing there. Im assuming this will affect my fluid velocity. Im right to think I need to get to computer correct before I attack anything else in regards to speed? So basically my problem is as before slow/no force top boom, slow tracking, slow bucket dump, double main boom regular speed but will "fall" when first engaged after tracking. Aside for the double main boom, everything seems to be proportionally slower. After replacing a solenoid behind cab on the manifold block I had full use of machine for the rest of day [hour maybe? It was probably coincidental] Then shut down with everything curled in, came in next day, same problem symptoms. Where is the arm regen and it's check valve located? I want to try to cure the arm swing.
You will NEVER get all the contamination out without a complete teardown of every component, and cleaning every single hose throughout the machine. You would be surprised at how much contaminants will stick in some of the smallest places, only to be released into your system when the machine warms up, the hydraulic pressure spikes, and the vibration of operating it.