I have a PC210-6 and recently I am having this strange behavior on this machine. When I move the arm in and the boom raise at the same time I have the boom that stop moving. The machine was not like this before, anybody has seen this before. Need a solution if possible
You most likely have a bad compensator on the boom circuit.
check first swing priority switch is on also john said please change this valve (number 18 of picture )
I checked number 18 and 25 and didn't find any problem on them. What do you mean by swing priority switch?
if swing priority mode change on, reduce the boom speed. are you check compensation valve interchange?
I didn't interchange PC valve. But I don't know why I have to change the number 18, I think this one is for the boom lower and not for the boom raise. Anyway, have you ever had this specific problem before? did you find a solution for it?
Interesting, but hard to find out a solution. I worked hard on a similar problem but with no result. Anyway, if you find a solution let us know
yes. you know boom load is larger than arm in.therefor without compensation valve system, arm and boom compound operations arm should move firstly end of there travel and boom raise.
Why arm in and boom raise worked together before
i think your machine compensation valve system works properly before. how is travel deviation, check also pump MERGE-DIVIDER solenoid.
I checked all the pressure compensation and all the solenoid. Have you ever had this behavior before? Anybody had this problem before, is it normal on komatsu machine to have this behavior?
I heard people saying they changed all pressure compensator and nothing changed in the behavior of the machine.
The compensators are just a loaded lift check valve. When a function is operated part of the pressure oil is plumbed to the back side of all those check valves. The highest pressure function is put against all those checks so that any low pressure function such as arm in has to reach the same pressure as the boom raise function before it will move. That's why they call them pressure compensated check valves. Your symptom tells me that one of the compensators is leaking that high pressure oil off back to tank. When this issue came up in the past the dealer people would first put new seals in all the compensators. If that didn't work they started replacing all the valves one by one until the problem was fixed. Needless to say that made a Komatsu with this problem very expensive very quickly. You can try the seals first and then buying one or two units and swapping them till the problem goes away. I don't know any other way to do it. There are people here at times that might know a cheaper easier way. I know there are lots of people who would also like to know.
If resealing compensator will fix it I'll do it. If changing them will fix it I will change all the compensator. But I already checked them and I didn't find any serious damage on them. I also checked pump pressure and it is 320bar on both pumps, if there was a damaged compensator the pressure should drop no? By the way if someone on this forum knows a cheaper way to do it please let us know the technique.
The compensators don't have anything to do with the pumps other than that pressure oil is also load sensing oil. If you dead head a function the pumps will go up to load sensing pressure and destroke.
This should be a classical problem on komatsu excavator that use CLSS. I think there should be an easy solution that someone alreday found. Anyway I will keep working on and will see
I already checked all compensator and didn't find any damaged seal. I also relieved each actuator to see if other circuit move. If there was a bad safety suction the relief pressure on corresponding circuit should decrease no?
By the way, why the boom raise+arm out work together and also boom raise+bucket curl work together? here also you have one actuator having more pressure than another and they both work at the same time, no?
Any news
When I measure LS pressure of the boom raise (teeth on ground and start the boom raise) with no load, at min RPM I have 70bar and at max RPM I have 120bar. Is it normal like this?
You have a problem with your arm counter balance valve you can buy a blank valve from Komatsu that does away with this it was a modifiction recall from factory I will see if I can dig out the part number for you Stephen komatsu mechanic
Hello Stephen, did you have any luck with finding the Komatsu recall text and the blank valve part number? I have a Komatcu PC210LC-6K with pretty similar symptoms of not having boom lift while arm in or bucket curl. Thanks!
Hey mate, I've had this before after arguing with older other techs who said -6 isn't the same as -11 when I was in a supervisor role, it won't be a comp valve comp valve will cause other function to move, remove the arm timing valve there are orings on the spools that blow out