This topic contains 12 replies, has 7 voices, and was last updated by Nathan 4 months, 2 weeks ago.
- August 8, 2013 at 9:03 pm #25943
Hello, I own a hitachi Ex200 lc-5 and I am having an issue with the hydraulics. When the hydraulics warm up, the boom will not boom down slowly; it jerks at the start. Once it’s engaged, it runs smoothly. The issue seems to only occur when starting to lower the boom. Can anyone help?August 9, 2013 at 3:18 am #28911
Two things came to mind:
1/ Air in the system. Have you cycled the boom up and down to evacuate the air? If there is air in the system, you will often have a burnt smell because of the diesel effect occurring in the system and the oil may start to darken or change colour.
2/ Have you added a different brand of oil. Sometimes the additives in the oils cause conflict and the additives drop out. If that’s the case, you may have to change out the entire oil package. Alternatively, some sample people can tell if the additives are sufficient for your oil and your machine. It very well may be something as simple as lack of lubricity.
Hope this helps.August 30, 2013 at 1:47 am #28940
look for internal leaking !!October 27, 2013 at 11:13 am #26859
As a Cat Tech I’m not familiar with the specifics of Hitachi hydraulics, however, I do know that there is very usually an antidrift valve for the boom up/down function. As the name suggests, the purpose of this valve is to prevent the boom from drifting down and the valve is only going to affect the boom down function. When you select boom down with your joystick, pilot or pump pressure must shift a poppet in a valve cartridge or shift a spool in the antidrift manifold block before oil will be sent to the hyd cylinder. Basically it is a load lock valve. If the valve is sticking, that could create your symptom. Sometimes these antidrift valves are a screw-in poppet valve cartridge and sometimes they are a separate manifold block that attaches to the hydraulic cylinder or in the cylinder lines near the cylinder, sometimes at the base of the boom. If it is the block manifold style, there might be a manual release screw on the manifold that you turn in to disable the lock valve just for testing purposes. Before doing this accurately measure the protrusion of the manual release screw so that you can restore it’s original setting. I suggest trying to obtain a hydraulic schematic for your machine to see what exactly you have for antidrift in that circuit.
Since boom up is not affected, I think maybe we can conclude that it is unlikely that the main control valve spool is sticking. When you select your boom down function and the boom moves and then you release your joystick, does your boom stop moving right away?October 30, 2013 at 7:20 pm #26913
Hello haven’t posted in a long while. I would agree with electron exciter. Check the load holding valve and the pilot if has external pilot. In general terms the load holding valve is just a counterbalance. In load holding applications on cylinders it should be mounted on the cylinder or at the minimum mounted close by with hard line.. They work with the pressure source to open the return to tank in your application. Pressure acting to lower the boom activated opens the poppet on the load holding side allowing return to tank. The higher the pressure to open the valve the jerker the initial movement.December 30, 2013 at 12:09 am #27493
It’s a spool sticking in pilot signal manifold change whole valve. It is cheaper than ordering parts for it.December 30, 2013 at 1:40 am #27494
yes your rigth Ron , its function as a counter balance or what we say automatic flow control,January 16, 2014 at 7:29 pm #27381
Did you get the load holding straightend out?June 18, 2016 at 11:22 pm #37056
HeyNovember 14, 2016 at 8:55 am #39204
I have this problem in machine ex 200 hitachi
All over function boom bucket and arm have suddenly operated like heavy starting operating jurk.I changed pilot pump,pilot filter
The jerk is there in there
What I do? help meJanuary 17, 2018 at 3:12 pm #44865
fuel filter oïl filterFebruary 20, 2018 at 10:32 am #44937
I own a tata Hitachi ex 200 lci(2012).der was a leakage in both pilot lever so I change both side seal and o ring. But now my left side pilot lever swing spool(pusher)got stuck while operating…plz suggestJuly 22, 2019 at 4:26 pm #50884
I have an Ex200/5, while operating it the other day the lift for main boom rams stopped and boom lowered to the ground, there is no leaks and the lever seems to still move like normal.
Can someone help