Hitachi 120-2 questions and anwsers

Hey everyone i bought a hitachi 120-2 last winter for 4,000 dollars which i thought was a smoking deal.
at first inspection the machine fired right up the idle up funtions worked. i moved the boom around and it seemed to bog the machine down. the guy i was with said it has got to be fuel filters."buy it" he said. so i did

one of the main reasons the people wanted to sell was because the machine had developed a new leak that was coming out of the middle of the undercarrage. they didnt elaborate on the bogging condition and said they just dealt with it.

I got the machine home i went through the fuel system drained all fuel out of tank changed filters and cleaned the bango fitting to. no change. i then started working on fixing all the leaks the main one was the center joint. i dropped it out and rebuilt it for around 100 dollars. I also put a new hydraulic oil cooler. i fixed 3 other hoses and now have a machine that no longer pukes oil

I then had a mechanic plug into it. unfortuanatly i wasnt there when he plugged in. he told me the pvc had no power. i replaced a 1 amp fuse and i got power to the pvc and it improved the machine alot but it still bogged mainly when you use a function fast or get close to the end of the cylinder. the mechanic also pointed out some butchering to the inner harness. i decided i would go ahead and replace both inner and outer harness's hoping this would solve my dash 2 blues.

I also want to say that throughout this whole time i have been studying this forum like crazy. after the harnesses were replaced i noticed no diference machine still bogs under heavy hydraulics and its almost frustrating to run after running one that functions corectly. i have since then replaced the PVC, Pump sylonoids, angle sensor, and i plan to do DP sensor

The mechinic i used said i should hold off on doing any more work or replacing any more sensors untill i plug in. unfortunatly it will be monthes if im lucky before he will be able to come plug in.
i have been really considering buying a conversion harnesss to remove all electronics. not many reviews so i am a bit leary but it seems to me if i could remove electronics this machine would be perfect.

so if any one has any insight in the conversion kits or any insight on what i should do or try next let me know i also want to say thankyou to all the posts that i have gotten good information off of.

This is some pictures of when I got this 120-2 and some things I’ve done, as well some work I’ve done with it

SoutheastSavage said:

This is some pictures of when I got this 120-2 and some things I’ve done, as well some work I’ve done with it

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Hello,
Welcome to HEF.
In my opinion, I think if you want to repair (or rebuild) this machine, you should have a thorough understanding of how the hydraulic system of this machine works.
Actually its principle of operation is also very simple.
Anyway, you can download the technical documentation of this machine for reference here

LACHAU said:

Hi dude,
Welcome to HEF.
In my opinion, I think that if you want to repair (or rebuid) this machine,

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I would like to restore this machine to its former glory. Not sure if tracing wiring is more productive than just getting rid of it all together

SoutheastSavage said:

I would like to restore this machine to its former glory. Not sure if tracing wiring is more productive than just getting rid of it all together

Click to expand...

In my opinion, I think if you want to repair (or rebuild) this machine, you should have a thorough understanding of how the hydraulic system of this machine works.
Actually its principle of operation is also very simple.
Anyway, you can download the technical documentation of this machine for reference here

https://www.heavyequipmentforums.com/threads/hitachi-ex-swing-issue.85237/#post-916574

or you can download EX120-2 technical manual directly here:

http://www.mediafire.com/file/len6liz0wirx0bc/EX120-2+Technical+&+Workshop+Manual.pdf/file

LACHAU said:

or you can download EX120-2 technical manual directly here:

http://www.mediafire.com/file/len6liz0wirx0bc/EX120-2+Technical+&+Workshop+Manual.pdf/file

Click to expand...

Thank you sir I actually bought these manuals a while back but I appreciate the link. I have been trying to learn the ins and outs of the machine and I think I’ve come along way. But sometimes it feels like a uphill battle

Hello, I have an EX120-3, 1997 working perfectly with the conversion kit fitted. I don't know much about hydraulics tbh but I could send you pictures of the setup. Maybe the -2 is different from the -3, somebody else might know.

[QUOTE="Garter,

Hey garter I would love to see some pictures of your setup on your machine I think the dash 3 is very similar. Also if you know what brand your conversion is would be helpful. Feel free to post pictures to this thread as I want this thread to become a place to get good reliable information. If you can’t post pics to this maybe you can message to me or if you want my email I could give you that

Fair enough, I'll post here, it might be helpful to others. Starting tomorrow if the rain holds off

Garter. Thank you very much. I am assuming you bought your machine with the conversion installed or did you have some one do the install ??

Bought with it installed, could probably locate the guy that did it. I would like to understand how it works as well, so maybe sharing on here will be a learning experience for me as well.

Cool. Looking forward to seeing pictures and it would be cool to get some information out of the guy that installed the kit. It could be a major eye opener to 120 owners world wide

I have recently been experiencing problems with my “throttle motor “. EC motor stepper motor which ever you prefer. Some times it work great other times doesn’t work at all it will fire up at a idle when I press the throttle up buttons it will actually start idling down until it dies. Also seems to be making some grinding noises. I am wondering if I can put a manual throttle on my machine or if it will effect anything. Some times it works great so just wondering if anyone has any advice. I like the idea of manual just for the fact of less chance of failing

Here are a few pics

And a few more. The conversion kit has no markings and was recently fitted. I know it was ordered from china and cost about 650 Euro here. Front control panel buttons are the only ones that work. Top computer is plugged in, bottom disconnected (don't know if this makes a difference). Speed is good on the machine. I checked the movements of bucket, boom, tracking etc against the technical manual and they are within range. Hand throttle is easy to use, only slight problem is that you need to remember to turn off key when finished as the panel lights are still illuminated and could drain battery. Hope this helps, if you need more details pics let me know.

Garter. I want to give you a big thanks for the pictures and the information I hope this will take some of the guess work out of buying a conversion kit for these 120s. I plan to buy one and I will post pictures of the install as well as post any issues I come across the way. Cheers