Hello, I have a komatsu pc210lc-6e with a worn pump. I recently took it apart and to my surprise the hole or bore where the servo works on both left and right pumps has some scratches. In addition everything including the drive shafts are shot. I was told by multiple mechanics that this pump is no good and that I need to find a new pump or new case. I have looked all over and it's a pain in the butt to find a new one I was told that I can only get a new pump directly from komatsu which would cost more than what my machine is worth. I have found a few offers on Alibaba prices ranging from $2800 on up to $8k. Most say that they are rebuilt with all new parts but some say that they are 100% genuine NEW Komatsu pumps. Has anyone ever bought a pump from Alibaba or dose anyone have any experience with Komatsu pumps ? I am located in Ecuador so sending my pump put for an exchange unit is outta the question. Any help or thoughts would be greatly appreciated!
Judging from what little I see, you have a lot more problems than just the pump. Where did all the little pieces from that drive shaft end up?
I bought the machine like this the original owner screwed me. This problem was pre-existing so I imagine those peices are floatin around the hydraulic system. I already tore down and rebuilt the valve bank. The pump is out so as soon as I find a replacement Im going to one by one take off the hose and try and clean them with compressed air and diesel.
There was some design changes on those machines through time. You are going to need to provide a serial number of the machine to make sure you get the right pump. Good Luck on the project and keep us posted.
John c. Have you ever seen or heard of anyone retrofitting a Kawasaki pump to the komatsu machines? I have been offered this option on Alibaba and it's cheap. I did a little research online but I haven't found much info. They basically modify the bell housing to bolt up the komatsu engine
The Komatsu main control valve and support systems all tie into the function of load sensing. I do not know if a Kawasaki pump has provision to work with a closed center load sensing system. All the Kawasaki pumps I have had experience with were negative control, meaning the pump goes to maximum stroke when a valve spool is actuated. I think I would have to see how the controls in the proposed Kawasaki pump work before I could say it would work or not.
Volvos use Kawasaki pumps. So yeah, some at least, have load sensing capabilities. And yeah, they use CSS almost exclusively, except compacts.The trick is, is the kawi pump negative or positive control. We had both types on Volvo. Are the pumps equal displacement? Are the ports going to be in a similar position? Or is one going to point at an unmovable structure. Will the discharge hoses require deadhead accumulator hoses? Are you going to be left searching for a flex plate that no one makes? Just asking questions that could be pitfalls. Best of luck.
Hello all thanks for the feedback. Im just gonna risk it and rebuild my old core. I spoke with a few mechanics in the States and I was told that the scratches on the servo hole/bore can be smoothed out and that I might have some leakage but nothing that will greatly affect the performance of the pump. I have watched like 17,000 videos on youtube that go over the repair process dosnt seem to complicated. I do have one question on LAPPING. Is this process necessary when using new parts or is LAPPING done just to recondition old parts?
Are you mating two angled surfaces? That would be the only place I would consider lapping parts to one another. Other than that I would just use a very fine stone hone.
If you can feel the scratches it was always my practice to send the pump case out and have the bores sleeved and precision honed to specification. Leakage in those bores can cause erratic operation of the pump. I will lap a used piston and barrel assembly to the seal plate using 320 grit lapping compound when I see scratches and imperfections. Komatsu used to use brass barrel assemblies and it goes quick. The last pump I was into had steel barrels and I would guess those might need a precision machine to do the job.
I have not built one of these pumps so take this as you may, but as an experienced cnc machine shop owner manufacturing precision aerospace and hydraulic components, the level of precision in some of the pump components are WELL beyond hand work. Just getting something to "work" vs getting good life and performance is quiet different and I would encourage you to work as clean as possible. I have seen some monkeys on youtube building pumps outdoors on a piece of cardboard. NOPE! The fitment of an engine piston might have .002" clearance. The tolerance of a hydro pump piston might be .0001". Enough that careful thought goes into even accurately measuring that. The heat from your fingers will skew the result and a simple hand mic is not acceptable. You might think a "good lapping" is helping, but you might cause more harm. I would not hand work anything new unless there was some real reason to. I am not trying to talk you out of it, just warning of the tolerances involved. Force nothing together, take your time, and work CLEAN. We fit ABEC 7-9 precision bearings around here and one spec of lint can damage a bearing if in the wrong place.
It can but you have to modify a little bit.
Yes Sir, you are right. But Chinese factory have modified the regulator of KAWASAKI K3V pump to change from NEGATIVE CONTROL to LOAD SENSING CONTROL!!! Anway, we don't believe the product which made by China!!
Good day folks As I follow the thread it would appear to me that the issue is with the pumps and not the regulator, could you not replace - rebuild the pump and use the existing regulators? The K3V pump is almost a industry standard (Kawaski) Kind regards Uffex
So new parts should not be lapped if I understand correctly? Your right about those backyard mechanics tearing down pumps in the field not ideal for rebuilding pumps but I understand why they do it. Somtimes they really have no other choice. I finally ordered all the parts necessary to rebuild my pump. My only concern is with the servo bore has some light scratches I hope its not enoguh to cause serious problems. A few mechanics have told me to not worry and a few more told me I was gonna have a problem so im gonna risk it lol. John C. I wish I could send the case out to get sleeved and re-bored but there arent any qualified mechanics down here in Ecuador that can do that kind of work.
It would be nice to see these scratches you talk of. Without knowing more and exactly what they ride on, it is hard to say what to do. I will tell you a scratch in a bore like that will appear under a microscope like a freshly dug trench with a trencher. The spoil piles on the sides of that trench can act like a razor blade to an oring or scratch other new surfaces. A "little" blending may help but I would NOT go chasing scratches until they disappear. However, its entirely possible that the damage is far from fresh and the servo and bore have honed each other relatively smooth again, or at least removed the highs. If Orings ride on those scratches, I would bet it will reduce life of them a bit. Sometimes it just takes a wise and experienced "guess"...... What we use is a micro and/or layout fluids. The fluids will put about a .0001" layer of dye on surface and you can use that to determine highs and lows.
I've done my share of Komatsu pumps and motors in less than pristine environments and I kind of get a kick out of all those who say you have to have the cleanliness of a surgical operating room. All this seems to be from manufacturers who want to present a mystique that prevents people from trying to fix their own stuff. The servo piston being talked about here is just a piston with no seals on it that has oil acting on both ends. Scratches can cause problems but in Ecuador what are you going to do besides the best that you can. I worked for a company one time where the owner kept wanting to just make things work for awhile longer. His favorite saying was "what would you do if you were in Alaska?" I told him if he was willing to put up with the consequences I would sure be willing to try anything to find out how long it works. It's pretty amazing what you can do and how long it will take to go to total failure. The places on pumps where you have to be careful is on the piston and barrel assemblies and the seal plates. If you have scratches in the barrel and seal plate, you might be able to lap them clean enough to work. If you have scratches in the barrels themselves, you are going to have a leak that in time will cause erosion and a future failure. The other place you have to be careful of is the small parts of the pump control valves. Getting them back in to the right places and in the right directions can be a real pain. Lots of times there can be scratches there as well. Just make sure the parts move freely, smooth away any rough spots and do the best you can. Let us know how it turns out.
John, as I mentioned, I am not discouraging anyone, but as an instructor, I try to convey the "ideal" environment so people will understand, "if you are in a field and totally screwed, you can at least HELP the situation but building a wind block, temporary tent, work right after a rain, etc". It totally amazes me how many just don't have the aptitude for precision work. I just tore down an engine that the CAT dealer themselves over-bored. The bores were tapered and egged. Will the engine "work", probably. But that taper is going to cause premature fatigue of the rings, eventual blowby, and ultimate failure. I just believe in doing it right, but I think we all have been in bad situations. I agree that OEMs tend to imply only they have the ability. However, it is quite different to build one perfectly, vs build 10,000 perfectly. Just take your time. We commonly work on CNC spindles and very common for a "DIY" spindle to only last a year, but an OEM spindle will last 20yrs. What is the difference? The bearings are exactly the same! In most cases, they either got debris in the bearings during assembly or got debris against the radial or axial planes of the bearing races, which distorts them. Anywho, as John would probably agree, once you know how to "do it right", then you will know how to "wing it" and make it work.
Here are some pics of the scratches im talking about. Its hard to apreciate but if you pay atention to where my finger is you can see em. I have the whole pump taken apart in my apartment lol. The scratches actually seem to be old and smoothed out . They are not like jagged vallies they feel more like roling hills if that makes any sense.
The bore with the hole in it is control oil inlet and those scratches don't mean much. The bore you are touching with your finger is where the garbage has been ending up. With the piston installed, can you move the piston up and down in the bore? You shouldn't be able to move it anyway except back and forth in the bore. What does the piston look like?
The servo looks good except for some super light hairline scratches nothing deep. It only moves back and fourth no play up and down o anything like that.
I would say it’s worth a try to rebuild it.
Your pics are hard to judge but a few things. If the radial (running around the ID) scratches are original, that tells me a lot about the level of precision and function. Do you have the fitment spec for that bore/servo? I agree, it looks decent, but IMO, the best and easiest is to just MIC the components and determine the clearance. That may give you some piece of mind down the road if things still don't work right. I hate when things get botched, then the expensive guessing game never ends. If the servo is within spec, you can at least know it is right as rain. Aside from measuring, you can use thin strips of shim stock or even layout fluid on things to determine fit. You can get shim stock in the ten thous. Honestly, the bore looks like a .001" fit (pure guess) so as a very quick guess, if you cannot jam a .001" feeler in there anywhere, roll it. those hydro pistons/bores are what need serious consideration.
Hello I already bought all the parts. I am going to begin re-assembly next week God willing. I do have another question though....Whats are the torque specs on the cradle and other bolts? Where can I find this information?
I've only seen that in a Komatsu Pump service book. I don't have that so use standard bolts torques unless someone clues me into something different. You can check it out by bolt diameter plus sometimes thread pitch.