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Thread: 1992 Hitachi EX120-2 questions

  1. #1
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    1992 Hitachi EX120-2 questions

    Taken from the welcome section, a new member asked this:

    Hello All, should have started here first with some post, but just found this thread.

    My name is Tom. I have an office day job but I also own an 80 acre Christmas tree farm where I spend most of my weekends. I have two agricultural tractors. A little one for inbetween the trees and an larger one with a loader for general utility work. As far as the contruction side, we also have a Mitsubishi BD2G. Had to replace the undercarrage a year or so ago. That was quite a job, but you live & learn. Its a pretty capable machine, but when you start ripping out stumps it really beats up the machine. I tend to buy/start projects. My latest is a 1992 Hitachi EX120-2. Bot it real cheap, basicly as a parts machine. Did a bunch of independant research on it first to find out the background as much as I could. It was missing the entire swing assembly and it had some damage to the control panel. Undercarrage is a little worn but for me probably fine for years. Pins and bushings look generally very good & tight. The hour meter reads 6200 and as best I can gather this is consistant with prior service records. As I write this it does not run, but I just had it delivered on Sunday. I have located all the parts I need to get it back in operation. I should have the engine running this weekend. I am a bit concerned about starting it back up without the swing motor in, but before I drop the money on that part I want to make sure the engine fires. I am also slightly concerned about the hydraulic system. The swing motor has been missing for a while and everything has been exposed to the elements. At this point all the hydraulic fluid has drained out. Thus:

    Questions for the experts. A) can I start the engine without having any hydraulic fluid in the machine (guessing no)? A-1) I would assume this might potentially damage the hydraulic pump? B) Should I try and flush/clean the entire hydraulic system before I start it and if so how? C) As far as the swing assembly goes, is there any cleaning or regreasing on the turntable I should do before installing it, remember this has been fully exposed to the elements?

    I did buy a manual, but I screwed up and bot the EX120 or -1 manual and not the -2 manual. There are enough differences in these models that I do not feel comfortable enough with the older manual considering some of the things I am going to need to tackle. Sooooooo, if anybody has an electronic verion of the -2 manual they would like to share, I would really appreciate it. I saw a -3 manual on flea-bay but not sure what the diffrences are between the -2 & -3 machines.

    Thanks, and glad I found this resource.
    Tom

    I thought he may get more responses in the ex section, BTW Tom , now you have three posts you can start your own threads.

  2. #2
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    O k you Cannot start it without hydraulic oil or you will be buying pumps. You can start it if you add oil and cap off the lines that went to the swing motor. It should not have lost all its oil because the swing motor lines are off, someone drained the oil or started it. I cannot tell you how much cleaning the hydraulic system needs, If just those lines were off for a while then their is probably dirt in thembut it can't go to far if you are worried take the lines off, blow them out, reinstall them and cap them then start it You want to see if it works and how it runs before you buy a swing motor and swing gearbox right?, clean out the swing gear before you install the swing gearbox/motor there should be a cleanout plate up under the center of the machine and also a plate right in front between your boom cylinders or in the bottom of the toolbox for you to remove and pack the swing gear with grease. It will take about 6 or 7 lbs of grease and you rotate the machine and pack some in there then rotate a bit more and pack some more in till you have gone all the way around. Use a stick do not stick your fingers in there. the grease nipples around the swing bearing only grease the swing bearing and will not put grease on the swing gear. Also on top of the pump there is a plug to fill the pump housing with oil before you start it

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    A big thanks.

    I just happen to find this using a google search looking up some additional info. I really need to explore this site more than I already have. I am a member of a few other forums and some are good and some, not so much. This is turning out to be a good resource.

    Thanks WSM that is very helpful info. I have a complete service manual on order. Your note about capping off the lines confirms what a local Hitachi mechanic told me yesterday. He even gave me some info about the cap sizes. The info about packing the bearing is "Gold Jerry, Gold!"

    Although I had hoped to fire it this weekend, that is not going to happen. There is just too much to do yet to safely fire it. Also I went to the local Deere construction dealer yesterday and purchased a new ignition and I think they gave me the wrong one. I will find out tomorrow.

    One more thing I did not mention was the fact that they took out the gear reduction on the drive motors to move the machine. I have not put those back in yet either. I will update as I progress.

    Thanks again
    Tom

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    When hey took the final drive cover off all they had to do was pul the little axle in the center to move it is that what they have done? and when you put the final drives back together use good quality oil ( I like to use synthetic 75W140 ) most people never change the final drive oil enough and believe me it takes a beating so changing it never hurts

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    They took out the splined shaft and the three gear assembly. Not sure of the proper name for but it looks like some sort of reducer. Probably not bad that I have to change out the oil in there anyway. I have some cleanup to do before I reinstall them as well. I have only been able to work on the machine one day so far and that was mostly just an overview to see what I got and what condition everything is in. Also to get a little more familr with the machine. As I am sure you can relate, things always to takes longer than you think. I just want to take the necessary time to do things correctly. I have to assume that you would use something like RVT to seal up around it to keep the oil from leaking out.

  6. #6
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    yes it must be watertight, so seal it good but do not apply so much sealant that you have big globs of it sqeezed out inside the cover, When you put the swing gearbox back on you also need to seal it. And yes it is a reducer it is called a " Planetary " And RTV sealant is what you would use

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    check inside the final drive cover plate for teeth marks around the perimeter. there is a spud in the centre as a guide for the splined shaft, when it wears the shaft tries to drive outward, and the planetaries marks the cover.

    i have an old post with pictures of the inside of the final drive... ex120-1 however, not sure if the -2 is the same.
    I find it easier to refill with gear oil when the filler hole aligns with a gap between the planetary gears, roughly 3 or 9 o clock position.

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    Quick question. I am picking up some plates and caps to block off all the exposed hydraulic lines. I have the JIC caps no problem. I would like to pick up the J518 or splint flange cap plates this afternoon. I am told they are #8 but have no real idea. Can somebody help me out with sizing so I can call my local hydraulic shop an make sure they have them before I drop in? Also I see there is a 61 or 62 although not much diffrent in size it probably still makes a diffrence. Again this would be in and around the swing motor.

    Thanks in advance
    Tom

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    Yes there is a difference in code 61 and code 62 so measure the diameter of the hose flange and messaure the thickness of the flange. Code 61 is a lower pressure rating than code 62 I am not sure of the hose size off hand because I usually work on Hitachi's EX200 and UP. The bolt spacing is also different between code 61 and code 62. I have a Hitachi parts cd here and I will sick it in the computer and see if your machine is on it. but it might be easier for you to pull the hoses off at the valve and if you do take a hose with you or the flanges. Also when you by the plugs try and buy the ones with a little plug in them that way you can always use them in the futerw with a pressure guage for testing. I am at nhe@nor-del.com if you want to e-mail me direct I will senf you the dimensions for code 61 and 62

  10. #10
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    Tom a #8 code 61 the flanged head diameter for the hose end is 1 3/16" and for code 62 it is 1 1/4"
    For the #12 hose the flanged head diameter for the hose end is Code 61 1 1/2" and code 62 1 5/8" You understand what I mean? the diameter of the very end of the hose fitting is the flanged head diameter. Hope this helps

  11. #11
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    Yep that does help. I may just have to put this off until next week after I have a chance to get more specific data from my machine this weekend. There is an outside chance I might be able to fire things up on Saturday and just wanted to have all my ducks in a row before I go to the farm.

    Thanks for checking.

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    The main hoses going to the travel motor on that machine are ORS (o-ring seal) or ORFS (o-ring face seal) which ever you prefer to call it. Not a code 61 or code 62 split flange. The o-ring is a T77858 part number. (deere #). After looking on line it seems to be a #12 ORS.
    .http://www.birminghamseals.co.uk/ind...ge=orkcarrykit The case drain and the travel shift are JIC.Take a #4 #6 and a #8 for the case drain and travel shift lines and you will have it covered.

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    Does anybody have a wix or Napa filter code for the suction filter element in the hydraulic tank? I have replaced the other but need to get that one as well.

    Thanks in advance

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    So I finally got things sorted out a bit and all the open ports closed off. Mind you when I bot this excavator, I bot it for the price of a parts machine so I donít have too much into it, but I also do not want to get burned by it fixing every last thing only to spend $20K fixing an excavator that is only worth $20-25K. I have already spent more money getting it to this point than what I had hoped for so I do not want to spend a lot more before I decide if it is worth continuing. First let me cover everything to date I have had to fix to get it running and mostly functional.

    -Reinstall the planetary drive gears and refill with oil
    -Block off several ports/hoses in and around the swing device
    -Install new batteries and put in a battery disconnect switch.
    -Replace the key switch
    -Repair the wiring on the controls panel & reinstall
    -Install several fuses in the fuse box that were missing
    -Re-install the ĎA Solenoidí on Hydraulic pump
    -Replace two hydraulic hoses on main boom
    -Drain Hydraulic tank & replace all filters
    -Fill with new hydraulic oil
    -Change Oil & Filters (old oil filter o-ring blew after less than 100 hrs as noted on the filter)
    -Reinstall a relief spring on one of the drive motors
    (I still have another part from the big-o-bucket of parts I was given that looks like it could have come from the drive motor and I have a slight leak on the one drive motor I did not have to touch. So this part could have come from the other dive motor. I only think this as it looks similar to a part that fell out of the other side.)

    Here is the good: The engine starts and runs fine. Idles up great and no blow by. The hydraulic pump does seem to be pressurizing the system fine. Controls to all hydraulics work as they are suppose to.

    Here is the bad: Could not get the drive motors to function. Hydraulics seemed a touch weak. Still have to purchase the swing gear and swing motor

    What I was hoping to do by this point was to put the excavator through its full paces. Check the boom, stick, bucket, thumb & track hydraulics and make sure they are all working and working well. What I got was a little less than inspiring but I have not lost hope yet One of the things that gives me a little concern was when digging a bit with the bucket the machine would bog down and then the engine would die. Could there be a brake or some other control not allowing the hydraulics to power to their full potential? Also, is it possible that if I miss-installed the ĎA Solenoidí, it could create problems as I have described? How can I check to make sure the drive brake is releasing? Should I hire a professional to assess the situation from here?

    Sorry for the long post, but before I spend the next $3-5K to do the swing assembly I want to make sure I didnít buy a great big pile of scrap metal.

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    Well I think I figured out one of the problem. Looks like I am missing the #14 fuse. This controls the stop motor. Stupid me

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