anton_baydak
Member
Hey I’m having weak power to all functions unless I’m dead heading some function. Just spent 6k for a new hydraulic pump with no fix. What is my problem. Thank you
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Hitachi 120-5 week hydraulics unless I deadhead any function
- Thread starter anton_baydak
- Start date
Kobe Steel
Senior Member
Are you able to provide some more details, if you can I'm sure there are a number of readers that could try and help you get to the cause of your weak power issue on your machine. If possible, can you give more details such as...
What is the full machine model ( EX120-5 or ZX120-5 ?)
what were the functions that were not working before the pump was removed and has this changed after the new pump was installed.
Is the machine slow to operate in all functions or only some of them.
Have you carried out any cycle time tests or pressure test on the machine after the pump was installed.
What is the full machine model ( EX120-5 or ZX120-5 ?)
what were the functions that were not working before the pump was removed and has this changed after the new pump was installed.
Is the machine slow to operate in all functions or only some of them.
Have you carried out any cycle time tests or pressure test on the machine after the pump was installed.
anton_baydak
Member
Hi. It’s a ex120-5. The diagnostics showed that the hydraulic pump#2 was weak. The new pump came with the test video showing good pressures. For example when I use my drives they are supper slow unless I hold open thumb button then it tracks normal. If I go to put boom down at idle I’d won’t lift the excavator unless I use any other function like open bucket or close bucket or even put pressure on swing. Then it lifts up
Kobe Steel
Senior Member
Try starting at the pilot pump and check that the pilot pump pressure is adequate before and after the pilot pump pressure filter (these small aluminum filters bowls can be very hard to unscrew) , usually located in the pump bay. Some of the pilot oil is used to supply the main pumps positive flow control pressure via the main control valve.
the pumps flow control pressures can be checked during single travel operation off the ground to confirm if the flow control signal is being sent to the right pump at the correct pressure, usually 25-30 bar signal will put the pump at maximum displacement.
the pumps flow control pressures can be checked during single travel operation off the ground to confirm if the flow control signal is being sent to the right pump at the correct pressure, usually 25-30 bar signal will put the pump at maximum displacement.
anton_baydak
Member
Checked all of that put in a new filter. Still same problem. Track speed is slow and boom down no power unless I hold thumb open or close or boom out or in then it tracks normal
Kobe Steel
Senior Member
measure and record the pump flow control pressures on both P1 and P2 pumps on boom power down while trying to lift the tracks off the ground, then record the pump flow control pressures again while doing boom down and holding thumb open or closed, what are these pump pressure readings after each test?
Do you by chance have access to a hydraulic schematic of your machine that you could post to me so that I can look in more detail at the the valve bank set up?
Do you by chance have access to a hydraulic schematic of your machine that you could post to me so that I can look in more detail at the the valve bank set up?
Diesel Dave
Senior Member
Kobe Steel
Senior Member
Info received. Its a big help, Thank you Dave.
NikinNZ
Member
Hello All, excuse my ignorance but i presume this is the main hydraulic pump on my Hitachi EX120-5 , it has a dip stick on it and the oil is very low, what oil does it take? it is just standard hydraulic fluid or special oil?
Also my machine keeps on cutting out then i try and drive forward (after about 30s-1m) if i stop moving it comes back to normal revs, someone says it may be a solenoid? next question, where do the solenoid valves hide?
Not used to these machines as you can tell....any help welcomed.
Also my machine keeps on cutting out then i try and drive forward (after about 30s-1m) if i stop moving it comes back to normal revs, someone says it may be a solenoid? next question, where do the solenoid valves hide?
Not used to these machines as you can tell....any help welcomed.
That is NOT your hydraulic pump......that is the swing transmission. Look for the main pump on the back of the engine.
Diesel Dave
Senior Member
You can download a free copy of the EX120-5 Operators manual from the Deere bookstore.Link below,
https://www.johndeeretechinfo.com/search?p0=model&p0_v=Ex120-5&pattr=p0&page=0&sort= .
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Your description of the machine performance issue is not very clear , please try again. What’s the machine serial # ?
https://www.johndeeretechinfo.com/search?p0=model&p0_v=Ex120-5&pattr=p0&page=0&sort= .
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Your description of the machine performance issue is not very clear , please try again. What’s the machine serial # ?
NikinNZ
Member
Yes i found it, i have no idea what is going on with this machine, it will run beautifully (engine will) but as soon as you drive it (well after about 30 seconds) or use the digging arm, the engine starts to stutter and eventually stall. Ive put all new filers on it, checked the little plastic filter gause on the fuel line etc and even changed the injectors, same problem! im pulling my hair out with this one, someone suggested the solenoids?
NikinNZ
Member
Thank you very much dave i will download that now. Here is the issue in a nutshell:-
1. Engine starts and runs perfectly.
2. I can drive forward (or back) but after about 10-30 seconds the engine will stutter and eventually stall.
3. If i sit still and then operate the digging arm, it will do the same after about 10 seconds.
4. If i just leave it sitting still (not using any hydraulics) it is totally fine at any revs.
Since this problem i have changed:
The Oil and filers (both hydraulic and engine)
The fuel filter
Thy hydraulic oil
The lift pump
The injectors
Still got the issue.
Diesel Dave
Senior Member
Sounds fuel starvation related. Was there much crap in the banjo bolt screen at the fuel transfer pump inlet ? Whats the inside of the fuel tank look like ?
Try running it with short hose from a clean 20L pail
Try running it with short hose from a clean 20L pail
Last edited:
NikinNZ
Member
Thanks Dave,
That is what it feels like, but nothing major in the bolt screen at the transfer pump inlet (put a brand new one on), inside fuel tank looks OK, i may drain it down and clean it, lines seem OK, plenty fuel coming to the injectors when i prime them, also when it runs it runs nice, even on high revs and will continue to do so for as long as you like, it is only when i start driving, or using the digger arm that it stutters and stalls, that is what i find odd. I am at a loss with this one.
That is what it feels like, but nothing major in the bolt screen at the transfer pump inlet (put a brand new one on), inside fuel tank looks OK, i may drain it down and clean it, lines seem OK, plenty fuel coming to the injectors when i prime them, also when it runs it runs nice, even on high revs and will continue to do so for as long as you like, it is only when i start driving, or using the digger arm that it stutters and stalls, that is what i find odd. I am at a loss with this one.
Diesel Dave
Senior Member
Try running it with short hose from a clean 20L fuel pail
NikinNZ
Member
Great idea, yes i will give that a go tomorrow, great suggestion. Cheers.
NikinNZ
Member
I noticed that the Hydraulic fluid was overfilled (just above Max) i may also take some out and see if that helps.