I recently had to replace the instrument cluster as the original died and I could not read any info when I ran my machine. In the process the hydraulic fluid may have gotten pretty low and when I started the machine the boom would not lift nor the arm extend. It would come down and in and now I cannot raise them again. I tried checking the main pump for any air but the fluid was clear. I tried loosening pilot lines to bleed any air from them, but at idle not much pressure and only clear oil leaked out. I did let the machine run for 2-3 hrs hoping if the oil got hot it might work out the problem...but it did not help. I do not have any pressure testing equipment for further testing and have not run the diagnostic menu on the machine. I need advice on what steps to take next. I have not yet able to get a mobile mechanic out to look at it yet. Any good suggestions are welcomed.
Boom up and stick out are 2 different joy sticks. Not sure how to get codes out of display if possible without software. Unless if both those functions use a common ground somewhere in the cab, be worth checking, and even if it isn't you can rule that part out for the next round of problems. Schematics would help a lot if you can borrow or buy and worth it cause machines now a days always have electrical problems of some sort. Simon C
Good advice. I think this system uses actual pilot pressure lines to both joysticks but maybe there is an electrical angle I have not thought of. I will look into that. Hopefully I can find a mechanic here familiar with this type of machine.
If you are into pilot line joystick controls, then you probable need to find which spool is boom up versus stick out on the pilot lines and check if some rubber went and plugged the lines at the main control valve. Could check for pressure at those locations also. Simon C
I'd start with the simple stuff before worrying about the pump. Low oil can cause all sorts of odd hydraulic problems if it pulled air into the system. Just because the oil looks clean doesn't necessarily mean all the air is gone. The other thing I'd want to know is whether you've still got pilot pressure. If the pilot circuit isn't building pressure, the boom and arm won't respond even if the main pump is fine. One question...does it still swing and travel normally? If those work, I'd probably spend more time looking at the pilot side or the control valve before condemning the pump.
Have you tried putting a little positive pressure on the tank with a rag and an air line? Some shop vacs suck and blow, I have successfully bled a Hitachi that got air bound and got low on fluid. As soon as you stroke more than oil is in the reservoir, you are cavitating the pump and pushing air. If you have done that there could be air all over. The pilot pump is usually the problem. Might have to bleed it manually.
Using a vacuum to blow works, always have to remember that the hose could have something in it that is sitting loose and suddenly is in the compartment. Always better to use compressed air unless the hose is brand new and no dirt has passed through. Yes manual bleeding of hose after pump works well to get oil moving. Simon C
Great comments! Thanks for trying to help me!! I never thought about putting more pressure on the tank, but will give it a try. I've been a little scared to mess much with the other controls for fear of the possibility of pushing air into the other valve functions. But so far the other things work. I have control of the swing motor, forward and reverse tracks, the blade function, and the bucket. The arm did pull in but now will not extend. The boom did push down but will not pull back up. So it is just sitting where it is at until I can get pilot control over the boom and arm again. I don't have a set of pressure gauges to even consider testing things, so at this point I've schedule mobile mechanic for sometime next week. Because I have some of the other function working correctly I am thinking it is not the main pump causing the problem. I think it could be in the pilot lines on the boom and arm action only. But as was mentions they are on two different joysticks... so that has me a little confused. My big problem is that I am not very smart about how the pilot lines and the main hydraulic valves work together. Also, I don't want to make too big a mess trying to learn by breaking loose too many lines. Right now I'm using a lot of moving blankets to absorb oil.
I am thinking about trying to switch the boom up and boom down pilot lines at the joystick control just to rule out the pilot pump and trace the problem to see if it is at the MCV.
That year of Kobelco if I remember their is not much electrics that has anything to do with the hydraulics other than temp and maybe level. Will have to see if I can find some of my older manuals on it. Does ANY of the functions work or is it completely dead? If nothing works then look toward the solenoid for the pilot system.
Everything seems to work except the boom lift and the arm extend. Now that I have the boom down and the arm retracted.. .. they will not move back up and out respectively. There is nothing...at first I could hear some variation in the motor sound but now even that has stopped. Still I can tilt bucket, move tracks, and move the blade up and down, also the swing moves. But... I have not moved any of them too much because I fear what has happened might spread to other functions. I was wondering if something happened with the safety valve aspects of the boom and arm system. The pilot lines for those two functions on separate joysticks seems to have been affected. I am hoping that I can get a mechanic with some experience out here to look at it.
Now it has a hissing sound that is coming from somewhere inside the MCV. Definitely a seal blown in there somewhere. Next step will be to pull the MCV and put a full seal kit in it. Pretty sure that seals leaking are with the boom and arm function.
Could be a relief valve stuck open that you are hearing. For us folks that are not there, we can only suggest some things to check out and possibly get you going. Simon C
Forgot to say that there is mainly just seals between housings and on the ends of spools, and if any are leaking, it will usually be external onto the ground. Simon C