Evening. I have a 2011 Hitachi Zaxis 225 USR. Plenty of hours on it. I am having a problem with the hydraulics. The left slew went weak, bucket crowd went weak and the tracking went weak on one track. Got into the service menu to check pressures. Pumps 1 and 2 are both showing the same pressures of approx 31mpa. All pilot pressures approx the same at 4mpa. Have changed pilot filter and main filter. At one point it wouldn't slew left at all, but after working it that returned. All the problems go when the main boom control is operated at the same time. Engine is running well and not bogging at any point. The pumps are original and haven't been touched. Is this some sort of solenoid or wiring issue? Any help or guidance at where to start looking would be most appreciated. Regards John
What side track got weak , left or right ? Are you referring to the pump1 and pump2 control pressures ? Are you saying all the problems go away when using the main boom control ?
What side track got weak , left or right ? - Left. Are you referring to the pump1 and pump2 control pressures ? - don't know - will have to check again. Are you saying all the problems go away when using the main boom control ? - Yes.
Welcome to HEF by the way . Note the Pump1 and Pump2 control pressures when the problem is occurring with the bucket curl or the left track and also when using the main boom.
It might be along shot - but there might be strainers plugged on the pilot control valves. Only left slew problem - could be separate trouble, as cross relief valve. Because its the same rotational group of the same motor. Or slew brake release problem, depending on whether engine is loading when you try to slew
It's been ages since i've worked on Hitaci, and i am old and forgetful, But: was'nt there shuttle valves on DP sensor?
Does that thig has 1 or 2 PRVs in the DCV? i dont have any ZX manuals, only EX
Gents, thanks for all replies. Are you referring to the pump1 and pump2 control pressures ? - they are both at approx 4.2mpa.
The pump control pressures are that when the slow bucket curl or slow left track is occurring ?
Yes.