Along with this thread: D65S-6 I also have the opportunity to get a Hitachi UH122 The pins, bushings & rails look to be in quite good shape. Almost like a new UC was installed and then it didn't get much use. I have no idea why it was parked, but it has been sitting for ~25 years. Anyone familiar with these units any info is much appreciated. I assume getting parts for this machine is about impossible?
If it's anything like the UH 12 it would have been a great machine. The only UH12 left in the world and powered with a Hitachi engine is in New Zealand. That machine has been fully restored including engine and pumps. On this one the engine and pump parts may be obsolete but repowering and repumping could be a less expensive option. An early EX300 could be a donor. This digger looks very straight for its age, would be a shame to scrap it
Good day Many consumable- - wear parts are available on the open market other parts you will need to be resourceful and adapt or repair what you have.I suggest make a good inspection before you take ownership. Kind regards Uffex
I have a CAT 225LC which is a 25 ton machine. From what I gather, this UH122 is a 30 ton machine? I have not even tried to turn over the engine as of yet, will hopefully get to that this week. The current owner has no idea why the machine was parked, he inherited the lot filled with a bunch of old/parked equipment. Is the Isuzu E120 obsolete? I do see some parts online. I don't want to spend the money on parts/service books until I get this this home if I end up with it...
I'll bet those rails are going to be a bitch to get rolling.
I had a UH083 machine. Loved it and what a workhorse! Those Isuzu engines are the bomb and very fuel efficient. Best part about those machines is no electronics !! After sitting for so long be prepared for the girl to spring leaks everywhere.
Would a UH122 be in the timeframe where John Deere had an equivalent machine? Also, what is the difference between a UH122 & 123? I can't find much online pertaining to a 122 but can find info and videos on 123's...
In the Deere world , 790 was a UH103 792 was a UH143
I've had a look online here in Australia and can't find any E120 engines so it's fairly safe to say they're obsolete. Thinking outside the square a JD engine could be a good replacement if a newer Isuzu cost doesn't line up with your pocket. There's still plenty of these non-electronic engines available. Looking on the bright side the current engine could be good to go with a little TLC. These engines were good for 15-20000 hours if looked after before a rebuild.
So, someone help me out with this undercarriage: When I first looked at the machine, it seemed to be in decent shape. Sprocket teeth looked good, grousers on pads looked good, bushings have very minimal wear and they don't appear to have been turned.
But yet when I look at the idler, by the time the tension is set the idler is almost all the way out! The top rollers do look very worn: I measured the rail heights at about 4.25" Even like 120% worn I don't think the idlers would be that far forward??? I cracked the engine oil drain plug today and only got about 4-5 drips of water before it turned to oil, so that's a good sign at least.
I would not sweat that idler extension thing. Those tracks are not that bad, it's a runner if you get it running. I also don't think it will give you much trouble if it had antifreeze in it. Get it all operable and then use it to drag the crawler loader onto a trailer, roll it onto a lowboy and go unload the crawler loader
X2 on the idlers and the bottom rollers aren't to bad either. How many hours on the meter?
One the best machines Hitachi ever made. Knew a guy that dug pipeline with them. They were a little before the Hitachi/JD agreement. After the JD deal he had to buy 892 JD's because the 300 size Hitachi's weren't available in Canada. I think the UH122 was closer to a 200 size machine though. He didn't like the JD's , especially the engines nearly as much. He loved the Isuzu engines. I think the UH20 used 2 of the same engine. The one thing he added was a water separator/filter on the fuel line. Apparently the stock filter system could have been a little better. His 1st machine went well over 9000 hours and the injection pump had never been touched in that time. I think he was getting well over 16,000 hours out of them working in some tough conditions including permafrost. UH 122's and a 121 (no live swing) replaced 4 P&H H418's and a newer model H1250 with 6V-53 Detroits. He said the Detroits needed an overhaul after 3000 hours. He was pretty deaf and needed a hearing aid. 2600 RPM screaming Detroit vs 1650 RPM Isuzu. Huge difference in noise. I think the Hitachi's even had a radio.
No idea how accurate those hours are. All the pin joints on the boom & whatnot don't look like they have 16,000 hrs on them however. So maybe the 6000 hrs is somewhat accurate... I don't like the fact there isn't an oil pressure gage and just an idiot light. I think before I try to run this thing I will hook up a gage.
It looks like the hour meter may have been changed but hard to say. It's the last thing to trust though.
I looked at some images and videos of other UH122's and they all seem to have the idler very forward. That's very different from what I am used to on my CAT 225LC. I can see the idler shaft through the slot in the roller frame. I always thought where that shaft is in relation to the slot is an indicator of the UC wear for all excavators. i.e. the lder shaft should be near the center of the slot, etc...
With Hitachis when the block that the axle is in becomes flush with the end of the frame is what you look for.
Excavators don't wear tracks out like other track machines. They have internal pin & bushing wear which stretches the chain but externally looks fine.
If I get it running I'll try to take measurements to measure the pin wear. Seems like there is a lot of internal wear.
It looks like that machine was a UH10-7 according to serial #. Anything after 171-2004 is 1985 or later. That would make it's manufacture date same as the UH123, which was made for european & american market. The UH123 was equipped with the Hino EP100 which was same as UH143/UH12.
It has a ISUZU E120:
I had the UH143 since it was new. It was a grey market machine at the time because of the JD/Hitachi agreement back in 1980's. I brought it over from Holland in 1985. All parts interchangeable with JD792, except engine which was Hino. That Hino was one of the best running engine I ever had, and I had many Cats.
Do not attempt to start that machine if the hydraulic oil tank is empty, also the air pressure to charge the hydraulic tank must work or the main pumps will starve for oil and damage them. There are bleed plugs on top of each pump that you can crack open while machine is idling to bleed out air if system was empty. You do not want those pumps to cavitate/suck air.
The HYD tank has oil in it but no oil on the sight glass, not sure if it needs 5 more gallons or 20 more gallons... So is there a belt driven air compressor for the tank pressure? So far I have not bought any oil or manuals for this machine as I don't own it yet, still evaluating. I was going to try to turn the engine over this weekend to make sure it's not stuck. Thanks for the tips.
Such a negative attitude. All those tracks need is a smile and a can of WD-40.
Yes, compressor on engine but forget how it's driven. I think you have to remove bolts from top of hydraulic tank to fill, no cap like cats.
The 790 JD Hitachi version was the UH09 for euro market and UH103 for Japan. The 792 JD Hitachi version was the UH143 euro and UH12 japan. The controls on the Japan versions had the stick and boom opposite of Cat, like the JD TLB/backhoe.
Maybe I'm confusing the two machines then. I know I took a cap off and loked at in oil tank, but that must have been the Komatsu D65S-6 I am evaluating at the same time. I'll look for that cap, thx.
All the 2 control stick Hitachi UH series I've operated had the left stick opposite the current ISO pattern, stick forward and back to slew,stick side to side for the dipper. In this era they were fitted with a thru drive alternator and the compressor was bolted to it. The hydraulic tank only required about 2 bar pressure (about 20psi). Without air pressure in the tank it was OK to run the engine but not to operate the hydraulics until the pressure had built up to 1 bar. @etd66sthat hour is anywhere near correct that digger is bearly run in. Depending how much walking it's done there should be a lot of hours of track life left. If you do buy it and the idlers get fully extended remove a link off the chains and run it to 100% worn out
When you fill the hydraulic tank, the stick should be fully extended with boom down & bucket fully curled in for proper hydro level.
I went and worked on this machine a bit tonight. I took off the pan under the radiator thinking I could get a socket & breaker bar on the end of the crank to try to spin the engine. There was not enough clearance between the car frame and the rad shroud, so I took off the two small inspection covers on the flywheel to try to spin the crank with a prybar. I could only get about 5 tooth movement back and forth before the engine got stuck. I gave up on that and rigged up the two 4D batteries I brought with me to see if the starter worked. It worked but the bendix immediately got jammed in the flywheel and the starter was stuck. I removed the starter and with a remote start button tested the starter, solenoid and bendix with the remote start button, the starter worked fine with 24V. And the nose of the starter that was in the flywheel looks practically new, so it's not a very old starter in terms of hours on it. Once the starter was off I had better access to the flywheel teeth. I was able to use a bit bigger crowbar and was able to keep working the engine back and forth until I got past the tight spot. I was not reefing on this bar with a cheater pipe or anything, but it did take a bit to get past the tight spot. I then proceeded to turn the engine clockwise as I assume that is the way it spins when running (viewed from front of engine). I'll put the starter back on tomorrow and see if I can turn the engine over, see how it spins. The fuel is really old, not sure I should try to bleed what is in the tank through the fuel system or try to drain out what is in there and put in some new fresh fuel. I noticed the HYD tank has two bolt on caps, one with what looks like a pressure relief and one without. I assume to check the oil level (nothing on sight glass that I can tell, but it's pretty dark like the sight glass is discolored), I remove the cap without the valve on it? I don't want to really spend any money on fuel and oil just yet, so hopefully it has enough in there to run. I cracked lose the drain plug for the main pump gearbox, good clean gear oil no water. The left side track was so loose that I had to kick the chain over back on the front idler. I used one full tube of grease and I heard creaking like the slack adjuster was just starting to move but ran out of grease before I actually saw any movement. For reference, here is what the right track tension looks like: The front block that mounts the idler is about 1.5" away from the front of the roller frame with that tension. So maybe the UC is decent? Also, I bought one of those sets of keys with like 60 keys on it for all kinds of construction equipment. Only 3 of them would slide in, none of them would turn the cylinder. The owner can't find the keys. Anyone know what key on Amazon/eBay will definitely work on this machine?
Is the key round like the old ace lock keys on car alarms from years ago?
That's all good stuff, you got it barred past the rust ring pretty easy.
If you can stick a long wire or even a straightened coat hanger in the hyd. tank to make sure there's some oil would be best before trying to get it running.
Two of the 3 keys slide in easier than the 3rd. The two that fit the best but still won't turn look a lot like 70's GM car keys. One rectangular, one round. The third is a red key that has JDS stamped on it, I assumed a John Deere key. None of the three keys fit great like a normal key should, they only slide in with some resistance. This is what I bought: Equipment Keys I'll take a look how many terminals the ignition switch has. But maybe grab something like this to replace it? Ignition Switch
Spray some WD40 in the slot & on the key, work the key in & out, maybe tumblers rusty.
I sprayed some PB blaster in it yesterday when I tried those keys, maybe when I go back today it will be freed up. It just seems like one of those keys should work...
No luck with the keys tonight. Should I try to hotwire this or do I really need an ignition switch? I was getting 25V to the B terminal on the switch, tried to jumper to a few other terminals but nothing. I talked to the last guy to run this machine, it was 5 years ago, all he did was move it from one lot to another, tracked about 1/2 mile. Said it ran good. I finally got around to looking in the HYD tank, and unfortunately pretty much all the oil has leaked out the pivot assembly. The oil is not leaking from any of the hose connections that I can tell, it's leaking around the perimeter of that diameter change when it transitions from a larger to smaller O.D. Does this indicate catastrophic failure of some kind to lose ~50 gallons of oil over a 5 year period? Or does the pivot just need to be resealed? I was able to connect the starter back up, the engine spins but it still has a tight spot as it is not an even cranking. The joint where the muffler attaches to the exhaust manifold has a huge hole, and even though that is covered by a sheet metal doghouse, the sheet metal is louvered at the top so water could have found it's way though and exhaust valve in #3 or #4 cylinder. Does the fact it turns over completely mean I can just try to fire it up? Lastly, with the oil that low, should I not start the engine at all? I don't want to spend $600 on oil to fill the HYD tank at this point to have it all run out the pivot assembly. I'm no longer interested in the D65S due to it's UC being so worn. Thinking of asking the owner if I can take HYD oil from that machine and put it in the Hitachi. I don't think it would be anywhere near enough oil however. I'd still have to buy probably 25-30 gallons. The deal for this Hitachi is the guy wants $3500 and I also pay to have it hauled. So not as cheap as the other machine. Kinda stuck with it needing so much oil... Here's a video of how much it is leaking: Leaking pivot assembly
The pumps may be dry of oil with the tank being low and where the leak is. I'd be inclined to put some oil in the tank then pressurise it with air before starting. The swivel joint will need resealing but it's not a biggie at the moment.
How much oil do you think I need just to try and start? ~20 gallons? Anyone know how much oil the tank holds? I tried to Google specs but can't seem to find. I am assuming at least 50 gallons. My CAT 225 tank holds 80 gallons. But this tank looks smaller. The owner also has a derelict Daewoo DH220LC parked down the road a bit. I can maybe also scavenge HYD oil from that as well...
20 gallons should be heaps to get it started but probably need more after it's started and if it's a keeper.
This could be a good excuse to buy some cheaper hyd. oil from a farm store or Walmart. I don't think it's a good idea to use used oil out of another derelict machine. Perhaps pressurizing the hyd. tank to 5 to 10 PSI with air would show where it's leaking.
cut a barrel down and fit it under the swivel area. get it ready to attempt a start. Add oil as suggested. Recover leaked oil to re-use. bonus points for giving it a spray down with brake cleaner beforehand to minimize dirt in your barrel.
I agree it's not the best option to use old oil, I can't really justify buying $100's worth of Tractor Supply oil that still costs $60 per 5 gal bucket before I even hear this thing fire. As it is I am buying an ignition switch and a fuel filter (~$50 total). I've already spent about $100 on this project and want to keep it to a minimum if I can. I'm told the property changes hands in a couple weeks, so I really need to at least get this thing driven back to his other lot (about 1/2 mile) so I have more time to evaluate it. If I do have to buy oil, I'd use ISO46 oil? In the meantime I have looked for a swivel/pivot assembly (not sure what Hitachi calls them) for this UH122 and not coming up with any seal kits. I see a lot of parts for EX machines but not the older UH machines. Also, if I do pressurize the tank after putting enough oil in it to submerge the filter, is there a way to bleed the main pumps to make sure they don't have air pockets?
Well I was wrong on the capacity of the HYD tank: 100 gallons ouch. I'm not buying any oil, we'll see what the owner wants to do. He may just decide to call the scrappers.
Well, if the pennies are this much of a concern just jump the switch to get it started . . .
I talked to the owner and he's fine with me taking HYD oil from the other machines. So that's what I am going to do. In his mind they are all scrap anyways, he just wants them gone... Is there a chance that this center joint really gushes out oil when I try to track the machine for the first time? Or is this leak most likley just a housing seal leaking due to weight of oil above it?
I described the bleed process in an earlier post.
We just bought a used UH083, parts are very difficult. Replacement head piece for travel motor from searching to receiving was about 6 weeks from Korea. Replacement seals for final drives another 3 weeks from China. And we still haven’t gotten her up and running yet
Yes, this is a concern for sure. It seems like the UH machines are abandoned when compared to the EX machines in terms of parts availability. So at work we have two 55 gallon drums of Mobile DTE26, which is AW68 HYD oil. Would this be too heavy an oil for this machine? We don't build HYD machine anymore some might be able to get those drums.
For your purposes here I figure any oil will do . . .
yes that would be great. It is only a little thick for the coldest temperatures.
For the time being 20 gallons should be enough to start the engine. If the engine is buggered then you haven't thrown to much coin at a failure. Assuming the swivel joint is pouring oil out then you are going to have trouble moving it under its own power so formulate a plan B like pulling out the sun gear in the planetary and towing it. As for resealing the swivel joint a good bearing shop should be able to get the seals but not necessarily as a kit.
So, I found a rather suspect hose for the right side track attached to the center joint: I decided to take it off to see if I can make one at work as we have a Parker Par-Krimp machine and I have made many hoses with it for my other equipment in the past. I got one fitting off and I was letting the oil drain into a 2.5 gallon bucket. The oil just kept coming, it wasn't going to stop. This was not just residual oil in the hose. I was forced to reconnect the hose. I noticed Hitachi uses inverted flare fittings which are not common, I am betting they are metric as well. I don't think the oil should just be draining from tank through the swivel, nor certainly a drive motor hose. Those are pressurized via a hyd piloted valve. The only things under the swivel joint are the drive motor hoses and parking brake hoses, none of them should be gravity fed by the tank. There is no way the 100 gallons should have leaked out over the last 5 years with just a leaking center joint correct? This issue implies something else is wrong? A main valve is cracked open and not fully closed or something? Also, all the hoses on this machine have their original brass part number tags, they seem to be all original. Googling part numbers returns ZERO results. this is not a good sign IMO in terms of a parts nightmare this machine could be. Is this essentially a grey market machine??? Were UH machines not for the North American market?
Anyone know if that track drive hose & fitting assembly would need to be 4000psi or 6000psi capacity? Very huge difference in the price of the hose crimp fittings... I don't have a HYD schematic to see what the relief valves are set at for the track motors. Parker 43 series fittings are about 1/5th the cost of the 77 series. 1GU77-12-12 1GU43-12-12
Those fittings could be BSP. They look opposite to a JIC fitting. The threads are the same though. 4000psi hose should be ok IMO. Gotta be better than fixing the swivel joint.
A Deere 792 strait , main pump pressures were 3770 PSI
Ok, interesting. My CAT 225 iirc is over 5000 psi.
I think the center joint definitely needs to be resealed, but that is not a concern for right now (could be a disaster later if I do end up with the machine though...). That track drive hose looks like it's going to pop the moment I try to move this machine. Tried to clean up the center joint a bit more tonight:
I can only find a parts list online for a UH123 center joint, but looks very similar: Oil is coming out right at item 11, which looks like a bearing race.
UH series were very popular in N America. They are what established Hitachi as the best selling excavators in the day.
Not just N America but globally. In NZ they had 96% of the excavator market. Contractors who ran a 100% Cat fleet went straight to Hitachi when they got into excavators.
Then I guess it is strange I can buy any part I need for my 1978 CAT 225, but this (1985?) UH122 looks pretty impossible to find parts for, so far... Also, should I assume all the pipe threads on the air tank are BSPP? I have some tank filling valves that I can used wiht a tire air hosem but they are 1/4 male NPT. Not sure I can fint BSPP stuff by tomorrow when I try to start this thing.
1 out every 4 excavators sold was an Hitachi back in the day of the UH series machines. I think a thread pitch gauge would be a great asset to figure out what fittings your machine has. I'm not sure a Japanese machine would have BSPP fittings. I'm really curious if you've talked to an Hitachi dealer. Being that Hitachi are still very popular it seems like a long term dealer should be able to help you with a key and what size fittings your machine has.
Ok, so tonight I got the following done: 1) Installed a new fuel filter, and put in 10 gallons of fresh fuel. 2) I primed the system with the hand pump, bled the top of the filter housing of all of its air. Not sure the plunger is working all that great. I can build up some serious pressure when I prime my CAT 3208 in my 225 with the hand plunger, so much so that I can't push the plunger and further. This machine, I hear some kind of relief valve after using the plunger for a bit, never feels like it builds any pressure. Do I need to crack loose the nuts on the injectors and bleed each one individually? 3) I harvested 35 gallons of oil from the Daewoo excavator and put it in the UH122. I was monitoring the sight glass and the last 5 gallon bucket put me to the second red line, I assume the level is supposed to be between the two red lines with the boom and stick fully extended and on the ground, so there may be a bit too much oil. 4) I then checked the bleeder screws on the main pump housings. When I cracked them loose they both were full to the plug level. So I assume this means I don't have to manually pressurize the air tank before starting, I can start as-is and let it idle to see if the air pump is working via the gage in the cab? Here is a video of the top pump bleeder port when opened up: Top Pump Bleed 4) I greased the fitting in the main pump gearbox: 5) I checked oil level of the main pump gearbox, it seemed way over full. But the only plug seemed very low, so not sure I was using the correct level plug: Maybe HYD oil is leaking into the gear pump housing via a bad seal... 6) I checked both planetary gearboxes, the LH one was almost full to the correct level, the RH one however was very low, about 2.5" below the level plug hole. 7) I put more grease into the LH slack adjuster, I got to a point where the track won't fall off the front idler, but I have now put in 3 tubes of grease. There must be a bad seal as I am not really building up pressure like I can on the RH slack adjuster. I don't see grease oozing out anywhere, but that piston is pretty well hidden in the track frame, so not sure I could see that anywhere. 8) I received the new ignition switch from Amazon. That will be the first thing I try tomorrow. Previously when I wanted to use my starter trigger to crank the engine over, I had to disconnect the battery relay because I assume the batteries are disconnected until the ignition is turned to the on position? So I should connect that back up when I install the new ignition switch? I think I am ready to try to start this thing tomorrow.
That track would be really hard to adjust stuck down to the ground like that. Keep that in mind. It is always easier to lift that side, and that is also the method for setting the slack properly on our 120, for example. It sounds like you are ready to give it a whirl. Best of luck to you!
Might be a good idea to spin it over with the fuel shut off to get some oil circulated before starting. That's what I was told after my engine was rebuilt.
I got the machine running but wnen I went to drain the air tank it is full of hyd oil. Any ideas on that?
I wonder if there's a check valve on the air tank that's maybe faulty? Other thought is over time hyd. oil was siphoned into the air tank from temp. changes or a negative pressure on the air tank. Give some more details on getting it running. Did it smoke and how did it run, did it make weird noises etc. How long did you run it?
Bonus, you found more hydraulic oil!! I think you need to get the correct level in the tank and then check it out. Did you get air pressure?
Ok, so to airline from the compressor to the tank was bad. I guess the main pumps were filling the tank because there was no air pressure? I fixed the airline, draining the air tank of the oil and will try again. The oil level on the sight glass went down about 1/2 in. So I know where that oil went...
I got the new ignition switch installed and put all new fuses in the fuse panel I started cranking to get oil circulated. About after 1 minute of that cranking it started puffing seriously black smoke from that nasty varnished fuel left in the injector pump. Tried about two more times and it was wanting to start but wasn't, so I moved the throttle lever to halfway and it started. No either required. Once the varnish was out of the pump the exhaust cleared right up. It seems to run smooth and on all 6 cylinders.
Generally if a diesel is hard starting and/or cold you give it full throttle so it gets as much fuel as possible. Once it starts slow it down to around 1000 rpm's. I knew a guy who loved the Isuzu engines in his UH122's and a 121. 121 didn't have live swing.
I sure as anything wouldn't start slowing things down to 1000 rpm on a cold start. You start pulling the throttle back as soon as it starts popping. I wouldn't let it get past normal idle speed until it has run for a minute or two, or at least until you have full oil pressure and it has smoothed out.
I'm surprised that engine hasn't got glow plugs. Well done on the work so far.
^ well done indeed. with regards to leaking, I have seen more than a few examples of stuff sealing back up with some use.
It depends on the engine. I had Hino that was very warm blooded. To start in cold weather had to use the glow plugs 3 times and full throttle. Once it started you had to keep it at full throttle until it got up to about 1200 RPM, then you could let off the throttle and it would idle. If you let off the throttle too soon it would die. I'm not saying to let it rev higher and then slow it down. I'm saying let it get up to about 1000 RPM and then back off the throttle. The Kubota in my skid steer starts much easier with the throttle set at full but as soon as it's running on its own you can throttle it back. I don't think it even gets to 1000 RPM. A lot of manuals will also say to put the throttle to full for starting when cold. It doesn't mean start it and let it rev to the moon. The throttle at full just let's it get the most fuel to ignite.
OK, so the air hose I fixed was not for the tank, I heard a sound while the machine was idling scared me as I thought something was siezing up, turns out it was the air horn coming to life... I did move the machine about 20 ft. I had to rev it up a bit to get the implements working, I would make a small move shut it down to keep checking the main pump bleed plugs, the pumps always stayed full of oil. Here is a start vid after I had the machine running for about 30 minutes and after moving. It also shows the oil in the air tank issue, and you can hear the air leaking out of the canister under the engine: UH122-Start Here's a video of the air compressor after I switched the hose from the right port which had no air coming out of it to the left port: UH122 Air Compressor And this video shows that I think I have this air canister plumbed wrong: UH122 Air Canister This piece of old HYD hose was jammed on the air compressor port that has pressure coming out: I mistakenly hooked it up to what I thought was a line that would feed the tank, but went to the air horn. I was wondering why the connection coming out of this was for 3/8" air brake hose and where I connected it up was 1/4". I thought maybe there was a reducing union at some point in time. When I removed that hose and connected the one going to the canister, that's when I heard air leaking out of the relief valve in that last video. When I took that video I noticed a piece of 3/8" air brake hose that was sheared off, it leads to a port on the bottom of that canister. So maybe that is supposed to be the air supply to the canister? This is not simple, there are damaged air lines going all over the place, it's not as simple as one line going from the compressor to a regulator then to the tank... Here is what the plumbing looks like tot he HYD tank: I'm wondering if I can bypass all of the other pneumatic equipment and connect the compressor to the left side of that regulator to pressurize the tank? I still don't understand how the oil is getting into the air tank when that bung hole is so high up, much higher than the oil level in the tank. This is how much the oil in the HYD tank went down, it started at the top red line: It seems like a lot of the implements had air in them as they took a while to activate. I suspect that's where mot of the oil went. I lost about 1 gallon out of the leaking center joint while I messed with this thing. Total runtime was about 45 minutes to an hour, mostly at idle.
You really need to get some manuals or at least hyd. and air schematics. Great you got it running but that should have just been to see if the engine is OK. You could be causing more damage to other systems by continuing to run it without knowing what's leaking or or how the hoses are supposed to be hooked up.
Continuation of the previous post due to only being able to post 4 pictures... I added about 4 tubes of grease to the LH slack adjuster, periodically raising that side off the ground and spinning. I was confused that when I set it down the LH would not track under load, even with the RPM's up. It was jerky and barely moved forward but tracked backwards fine. I was working by myself and it wasn't until I got out and saw why it had a hard time tracking forward: The chain is loose on the sprocket and fighting the tooth engagement. I guess the slack adjuster piston seal is totally useless. This will make the machine hard to load on a lowboy. Is there a way O can manually jack the front idler forward temporarily? Couple of things I should not have done: 1) Went above idle with the air tank thing not sorted out. Though the pumps always seemed full. 2) None of the dash gages or idiot lights work, so no idea about oil pressure. There isn't even an oil pressure gage from the factory, which seems crazy to me... I don't think I can run this to load on a lowboy until I figure out how to plumb the air tank and stop it from filling up with HYD oil. I also need to find a solution for the loose LH track. I don't want the rails to fall off the idler when it's being loaded...
Yep, I get it. But from what the last guy to run it told me about the machine it may have been run this this by the previous owner for a time. So maybe the pumps are messed up already, hope not. My brother bought a Koehring 6608 from the same guy (again, super cheap, less than scrap value), the prev owner ran it without an oil cooler for many years. We had to rebuild one of the pumps.
I think this is the air line that is supposed to pressurize the tank: The way that this is setup, it seems both the HYD tank and that air tank receive only the 1.8 bar pressure out of the regulator. I thought I read the air tank was supposed to have 130 psi in it, then regulated to the HYD tank with ~14 psi.
If you lift up the side with bad track adjuster can you at least extend it? If so maybe there's a way to block it so it can't come back. Another possible way might be to pull it out with the stick of the hoe.
I mean I can probably lift that side up and get the idler forward with a house screw jack and some wood, but I don't know how I would keep it there when tracking the machine to load onto a lowboy. There is really no way to put something inside the roller frame from what I can tell. This is the only access: Get it forward again with a jack and then maybe tack weld in a plate with forks on it on both sides so the idler can't come backwards just to get the machine loaded and unloaded...
This picture shows a bunch of torn up air lines, as well as a port on the bottom of the air canister, or whatever it is called. I am wondering if that is where the compressor should be plumbed to:
Just for future reference the engine is fitted with glow plugs. The indicator for them is just forward of the start switch with the holes on the top, you'll see a wire glow when in operation. The engine must in pretty good condition if it starts after sitting that long without preheat. The probable cause of the jerkness of hydraulics is the lack of air pressure in the tank. Once you fix that it'll come good. Sorry I can't help with that as all the UH series I've operated the hydraulic tank was the air tank.
Yeah, when I was hooking up the new ignition switch, I believe the "R2" terminal is for when you turn the key backwards for glow plugs. I was not really trying to start the engine, was turning over to get oil circulated. I had thought I was going to need use either to get it started but it started puffing after about a minute or two of cranking, once I nudged the throttle up a bit it fired up.
OK, so I bought a pdf version of the Users Manual as the website I bought it from showed the table of contents. This is how the air system is supposed to be setup: Looks like the previous owner really butchered this setup. The machine currently only has one line going to the air tank, not three as shown in that schematic... And yes, the air tank is supposed to have 130 psi in it. I understand putting it all back to the way it should be, but just trying to get this on a lowboy... If the pumps were cavitating, would the oil get foamy? Chances are this machine was run for many years with this mangled setup...
Depends on how fast you want your turbo spinning before it gets oil ...
Yes. Considering the whole scenario you have going on, I would expect the oil to be aerated to some degree.
If the pumps were cavitating they would be very noisy when using any function
I ask because the oil is not foamy at all.
They are not noisy, but initially it took a while for the boom to lift and the bucket to curl. And quite a long time for either track to drive. I suspect there is a lot of air in the system yet after pretty much all the oil leaking out of the center joint over the years.
If the pumps are full of oil there won't be any cavitation because these pumps don't suck oil. It's more that they are pumping pressure intermittently if that makes sense.
Not all diesels will start up cold with the throttle at idle. Full throttle is just to get the most diesel into the combustion chambers so it fires easier. Once it fires and starts to run on its own then it can be throttled down. Some engines might only need 600 RPM but other engines like the Hino I had struggled to run 400 RPM and would burp and stutter like that for 10 to 15 seconds until it picked up speed. You had to let it get up to around 1000 to 1200 RPM on a really cold day in order for it to stay running. It could take up to 25 seconds sometimes. It never revved high initially and came back down. There are some diesel experts on here who have also mentioned putting the throttle to full for starting. Nobody is saying to let them rev. full throttle at start up.
Not uncommon for it take a few seconds or more for functions to work especially on a machine that has sat for a long time. Cylinders could creep and there could be other tiny internal leaks that it takes a little bit of time to fill the lines with oil and then pressurize the oil. My backhoe creeps after sitting for a few days and takes a couple seconds for the bucket to work smoothly.
If you can manage to straight walk it forward you can load it with the funky track. It does present a challenge chaining it down though. good on ya for resurrecting it.
We are discussing two different things. Giving an engine some throttle to get it started and revving it up are not the same. Many older engines need a little throttle to start. Most newer electronically controlled engines do not, and playing with the throttle will do nothing because the ECM will ignore the throttle inputs until after the engine is running. Revving a engine up on cold start in the way you are describing is poor practice. Because you believed your little Japanese diesel required it does not make it good practice. Good practice with your Hino would include things such as plugging the engine in or diagnosing why it didn't want to start cold. I have been working with diesel engines for many years, and I have been in many situations involving starting engines in cold temperatures, sometimes as cold as -30F. Yes, I have shot ether into them, revved them up and done all manner of evil things to get them running. Some of the time I didn't even care, and neither did whoever told me to GET IT RUNNING. It doesn't make those things good practice, and I would not just go and characterize some of those extreme measures as normal. Any time those measures are taken it should be with the understanding that it is very harmful to the engine.
I never said to rev. them up and I was talking in general not about electronic engines. My Hino was plugged in. It would spit and burp at very low RPM's sometimes up to about 30 seconds. The only way it would stay running was to wait until it would hit around 1000 RPM's and was running on all cylinders smoothly. It had a cloud of smoke so thick you couldn't see 5ft. 3 minutes later it cleared up and had no smoke at all. The engine was professionally rebuilt when I bought it and didn't use a drop of oil. Despite your thinking something is wrong with the engine that makes it a hard starter it is a known fact that some diesels are much harder to get going in the cold. Ih 282's and Standard Motors diesels in early ** 35 tractors are examples I know off. The Kubota in my skid steer is indirect injected and needs glow plugs on the 1st start if it 80 deg's. outside. Putting the throttle lever to full throttle makes a big difference when it's cold. Once it catches at I'd guess about 400 RPM I can move the throttle lever to idle. Same with the Perkins in my tractor. Only the Hino ever needed longer to reach a higher RPM where it stayed running. It doesn't mean there was something wrong with it.
My ford 1620 with 3 cyl shibaura is like that. Has to be set to 1000 RPM's to actually start, no matter the temp outside. Always have to use the glow plugs as well.
May I ask why the planetary cover is wet? Did you spill oil on it or is it weeping from the cover? On my UH143 it also has air tank with regulator like yours. If you pull up on the relief valve on top of hydraulic tank and release air pressure after you shut machine down, you will not lose as much oil from rotary manifold. Also pulling up on that relief valve anytime you blow a hydraulic hose will stem the flow of escaping oil. Nick
That is actually diesel fuel from a soaked rag I had sitting on the track above the planetary. The air system is currently not building any air pressure as the previous owner really butchered the air system plumbing. (in fact if you watch the UH122-Start video, at the very end you can see the air tank is actually filling up with HYD oil). I'm not going to have time in the field to re-plumb the air system and get that working properly, just need to get the LH track from falling off the sprocket and/or idler so I can get this on a lowboy. The slack adjuster seal seems to be totally gone, can't build grease pressure and as soon as I track the LH drive backwards the track is all the way loose again. My plan is to pump out the adjuster with the LH track in the air as far as I can get it and weld 3" x 3" x 1/2" THK x 2-1/2" LG angle tabs into the slot on the roller frame to keep the idler form moving back so far when tracking backwards. A temporary field fix to be able to manuever this to transport. As I previously stated, it seems the previous owner had been running the machine with this butchered air system for some time, not sure what kind of condition the pumps are in, but I am going to have to run it as-is to get it transported then deal with the air system later. If the pumps are shot then they are shot, I don't have much time left to get this machine off the property.
If this guy can get it done, you should have no problem. I’m sure your tracks are in better shape
@ etd66ss, excavators can be loaded onto a trailer with only 1 functional track if the rest of the machine is working properly by lifting 1 side and carrying it whilst driving the good side.
I had mentioned that earlier. It helps if the trailer is in a straight line with the excavator to start with.
I went tonight and was able to lift the LH track off the ground and get the idler forward enough. Next time I go I will take a generator and my stick welder and get those pieces of angle welded into the slots on the roller frame, one each side, to keep the idler where it is. The center joint dumps a decent amount of oil. I bet I will lose about 5 gallons loading this thing onto a lowboy. It dumps mostly when tracking. Both track motors work, but the LH seems a lot less powerful than the RH. I think that circuit is the one leaking so much oil. Another issue is this hose for the RH track motor: Not sure if I should replace this hose before calling out a lowboy and then having that hose pop... I looked on the Daewoo and I might be able to scavenge a hose off that machine, it has the same 60 degree cone fittings.
I was able to get the idler keeper plated welded in today. Tested and works, can track backwards without the slack adjuster collapsing fully. Not great welds I know. I had trouble with the vertical welding. I don't stick weld that often: The LH track barely has any power. I assume due to the fact the prev owner ran this machine without the air system plumbed properly, whatever pump drives that track is wiped out. I got this hose out for the RH drive, need to make a new one as I don't trust this one for loading and unloading to transport: Those BSPT threads were tight **. Took a crows foot on an impact gun to break it free.
A few good smacks with a hammer before wrenching helps to loosen those nuts.
The hose shop should be able to verify what thread they are. I doubt they are a British thread but could be wrong. I don't recall ever reading or hearing it's a pain to get hoses made for Hitachi's. On your vertical welds use a 6011 or 6010 and you can go downhill using a down and back up whipping technique. You're basically digging a groove and then going back and letting it fill up. Any other rods you want to go uphill. Make sure to use enough amps so you get decent penetration.
I did try that but the fitting is it a tough spot under the machine. The crows foot + 1/2 in drive impact worked really well.
You saying to run with the rod pointing down? I don't know that I have ever tried that with 6010, I guess I will next time. Trying to go downhill with other rods never worked for me, but I am no master, especially out of position.
you can check that out with a hand or a heat gun. If the drive motor is gone, it will pass a lot of oil and the return will heat up. Also note the temperature of the case drain from the drive motor. If all the other functions seem normal then it is likely the drive motor and not a pump, as a faulty pump will affect some other functions.
Rod is pointed up about 10 deg's to hold the puddle from falling but the progression is down hill. 6010/6011 don't get a thick slag covering and the slag isn't hard to burn through. Other rods downhill don't have much penetration and leave a concave bead. 6010 has good penetration and because the puddle freezes faster allows for more fill so you get a flatter or even convex bead.
Pretty sure these are the fittings I need to make the hose: I'll make the hose myself at work. I can get those fittings on eBay for a decent price.
Well the other functions seem normal, however looking at the schematic both pumps seem to run the boom & stick: When I lift the LH track off the ground it rotates just as fast as the RH. But under load it struggles.
The way the arm and boom hydraulics work is half the lever movement only one pump works, full lever movement engages both pumps. Once you get up and running properly you'll feel the difference in the levers.
My propel functions on Hitachi were weak when my rotary manifold was leaking. You might want to open the final drive plugs to check for hydraulic oil. If they are over full it would indicate track motor passing hydraulics into finals, another possible reason weak track motor. Nick
The center joint is leaking terribly. I hope that's all it is and not a pump or motor. Just need to limp this thing on a lowboy for now. Can dig into all of its problems once I get it to my place.
Both machines are close to being fixed up well enough for hauling, still need to make one hose for each and then hope no more hoses pop:
That's why the loader bucket looked odd. It appears to be a side dump bucket. Pretty rare but not the most desirable. For the hose fittings just make doubly sure they are the right ones.
yes it's a tipper. I've never seen a crawler with a tipper but Tucci had a few old JD 644b tippers.
I'd prefer a normal bucket, so much volume is taken away due to the side dump functionality.
Find out the shape of the rest of the machine before worrying about the bucket.
I think I'm on the final stretch of field work for both machines. Made one new hose at work for the UH122 and ordered a hose assy online for the D65S-6, as it was cheaper for the assy than ordering just the fittings off eBay:
hopefully the next pictures will have them on a lowboy.
I finally got the UH122 moved. The driver of the truck didn't like how janky the foot pedals were so he made me drive it on and off the lowboy. It was a bit of an adventure: One problem I have with the machine is the fuel system doesn't hold prime. It will run for a couple minutes then die. Have to keep manually priming the system. Plenty of fuel in the tank.
Check your lift pump bolted to side of engine. It's a diaphragm type. You can install electric and do away with it. You will have to take it out of the loop or the electric pump might push fuel through the broken diaphragm into the engine oil. Nick
I think I may have heard that vibrating one time when I shut the machine down. It's probably dry rotted etc.
Usually if the fuel tank is full you my not notice the problem. When the tank goes below half then it will crap out and you'll have the re-prime problem due to fuel starvation. Maybe the lift pump is still available. If you can't get your hands on a 24volt pump, just get a 12 volt one & hook to one battery, that's what I did. Nick
You also might have a biological problem that is restricting fuel flow in lines or screen in tank. You might want to cut the fuel filter open and check for slime. If that machine has been sitting it's very likely your contaminated. Nick
Those primer/lift pumps are repairable with rebuild kits available either Denso or Bosh. A darn sight cheaper and easier than fitting another pump. I have also seen rubber suction fuel lines delambimate internally which has all the same symptoms as you have.
I don't see a puddle anywhere, looks like a smooth move.
In my experience hooking up to one battery will greatly reduce the life of your batteries. When charging the batteries the one with the draw on it will not charge properly.
That little electric fuel pump won't have much effect on the battery, I had it connected like that for 10 years, never noticed anything. Those group 31 batteries won't even know it's there. Nick
I ordered a pdf parts manual online last night and I don't see anything about a diaphragm pump on the engine. I think this machine is supposed to use the air tank to pressurize the fuel tank just like the hydraulic tank? I don't really understand what is going on with items 10-19, my machine has nothing like that anywhere.
Can you post a photo of the fuel injection pump. All the photos I've seen of these engines shows a lift pump mounted on the injection pump which was typical of most Japanese engines of this era including Hino, Komatsu and Isuzu.
Yep, lift pump on my 1985 hitachi UH143 with Hino was mounted to block just under the main injection pump. Easy to change provided thats the issue. Nick
I'll get a pic of the engine soon, but from the parts manual the only pump connected to the injector is the hand primer that pumps fuel into the filter housing: This is the canister I sometimes hear vibrating after I shut down the engine:
If what you are calling a canister has the dome nut on the top is a centrifugal oil cleaner and should be cleaned out at every service. The gunk inside has to be scrapped off. Back to the lift pump, what you have circled is indeed the primer but it's also the lift pump and driven off the injector pump so it's a combination of both. On the inlet side is the famous or infamous screen in the banjo bolt which is also worth checking at this time. In the lift pump there's 2 nylon plungers that get pitted causing a loss of suction. European engines use this same set up. I've put a Denso kit into a Scania truck engine with a Bosh fuel system so I know they'll go the other way. A kit would cost about 20 bucks and about 1|2 an hour of your time. PS the plunger has to be screwed down when not in use, leaving it lose will cause it to wear out.
OK, I figured that it needed to be threaded down when not manually pumping, been doing that. What I find annoying with the parts manual I just bought is it does not have parts breakdowns for the HYD pumps or engine parts. I guess I am used to CAT manuals that have EVERY SINGLE PART that is on the machine. So do I have to find separate parts manuals for the Kawasaki pumps and valves, as well as the Isuzu engine? I see where aftermarket pumps are available: But I'd rather just find a rebuild kit etc.
We replaced all the fuel lines on our Euclid C-6 dozer due to internal delamination. The machine got to the point where it would run 5-10 minutes before fuel starvation would cause the engine to die.
Very strange your parts book doesn’t show the hydraulic pump breakdown. The Deere 790/792 parts page’s have the pump complete breakdown a bit further back. Just for giggles, what’s the part number for the complete individual hydraulic pump ?
It seems anything that has its own serial number tag on it (engine, swing gearbox, pumps, valves, track motors, etc) are not broken down in the parts manual, they are just listed as a single line item. I believe this machine is pre Hitachi-Deere partnership, so going to be a nightmare to find parts as everything I'm sure is obsolete.
Ur right Hitachi generally has 3 parts books per machine. - Engine (by engine model) , - “ Parts“ - “ Equipment component parts “ , which has all the breakdowns .
Some lift pump/primer pics: Looking online this is the closest match I could find to a lift pump parts breakdown: 105237-1370 I assume item 5 (pump plunger) would be the culprit. I was looking for an engine serial number nameplate, found a stamping. I assume the numbers after the E120 is the S/N?
That's it as per my last post. The banjo fitting with the rubber hose has a screen inside it. Check that it isn't blocked.
I will check that. But if it were blocked doesn't that mean manual priming via the hand pump would not work, yet it does?
The manual hand pump may have enough pressure to push a small amount of fuel through the obstructed screen. That would certainly explain why it would run for a short time only.
Here's hoping it's just a clogged screen. Both this machine and the Komatsu D65S have fuel delivery issues. I drained a bit out of both machines to check for water and sediment, but like many have said, maybe hose delamination.
Both will have pretty much the same fuel system.
Maybe it's time to check the tank your pumping from to fill your machines.
I currently don't have my own tank, so been doing the 5 gallon jugs from a Mobile station etc. However, the majority of the fuel used to get both these machines running was fuel from the Hitachi. Very old, varnish smelling stuff. But neither machine had water. However the Komatsu D65S-6 did have a lot of black flaking material coming out of the tank drain, yet the metal screen leading to the float tank was not clogged, so dunno.
Fresh fuel would be much better and help clean up the lines, especially if you added some diesel conditioner to it. I know you're not trying to spend too much but using who knows how old the fuel is, is just making things harder for yourself and contributing to more problems.
I'll fix both machines up properly at some point. Just need to get one more moved to my property. Both of these machines are long term future projects. Don't really need them, but I have the sickness...
You have the iron fever. Somehow I've managed to avoid it.
Hopefully the sickness doesn't deplete your finances too much. The Hitachi is good machine if you can get it sorted out economically. It was one of the best excavators ever made.
All said and done, with what I have into them to get them functining well enough to load and unload, and what it cost to haul them, I am probably at about $5200 total for both, a little over half scrap value. If I get them working and make use of them someday great. If I don't and end up having to scrap them (don't want to), then so be it. These days I really only go for the very good deals, where ppl need machines gone off their property etc.
Well, certainly seems like the screen in the banjo fitting was the likely issue: Cleaned up all the parts: However, when I used the hand pump I could feel I was building more pressure and then the seals in the primer pump let go and it is dumping fuel. Trying to talk with FridayParts for a rebuild kit but it seems they only have the entire pump. I suppose I could take the pump apart and see if I can measure up the seals, easy if it's all o-rings.
The screen can be unscrewed from the bolt for proper cleaning. It's the nylon plungers that may need replacing and should be available from a good fuel injection shop. They should stock the 0 rings and copper washers.
Looks like you found the problem. I had a similar screen in a hex fitting on my Cat that gave me fits. I wasn't sure what people were saying until one guy explained exactly where the screen was. It almost looked like it had little strips of wood in it. Machine would idle but die when I tried to move it. Took about 40 minutes to move it about 1/8 of a mile onto some high ground to work on it.
Just thinking about this machine as a future project and doing some initial research. Would this machine be considered a Grey Market machine? It has a label on it that states it was built for export, so I am assuming no? Also, it seems the UH123 vintage is when Hitachi partnered with JD, so parts for a UH123 seem to be more readily available than for a UH122. I have a UH122 parts manual and searching part numbers online reveals absolutely zero results, quite concerning (part numbers were never digitized, they reside in paper catalogs only). Is it likely the case that JD will not be able to help me at all with parts for this machine? I have yet to contact a JD dealership, but I think I already know the answer to whether or not they could help with this project. Lastly, I have been looking into the Isuzu E120 engine. I see engine kits online for an E120, but they are all 4 cylinder kits, where the E120 I have is 6 cylinder. This makes no sense... If the answer is to re-power & re-pump this machine, not sure I'd ever be taking it on as a legitimate restoration project, would much prefer to restore to original. I don't need the machine for any specific reason, just grabbed it because it was going to get cut up and scraped and thought it might be fun to fix up and use it alongside my CAT 225 when I dig my next pond. Excavators are pretty handy to have...
Isuzu is a great engine. Shouldn't be hard to find parts. The 1st JD Hitachi machines were JD790 and I think 792. Not sure if there was a competing Hitachi machine in N. America. I know that later on you couldn't buy a EX300 Hitachi in N. America, you had to buy a JD892 instead. The JD engine wasn't as good and was mounted higher meaning the pumps had to work a little harder to draw the fluid up.
I see that 6RA1 engines are listed alognside E120 engines, they have the same bore & stroke. Anyone know if the parts interchange between the two?
Is there an Isuzu distributor you could contact? Just because you can't find parts online doesn't mean they're hard to get. What about talking to a Hitachi dealer? UH121, 122 and 123 were extremely popular machines. I think the UH20 used 2 of the same engines.
Is this any help? https://nl.aliexpress.com/item/1005...2&afSmartRedirect=y&gatewayAdapt=glo2nldhelp?
I have emailed a local Hitachi dealership to inquire about how much support I can expect on this machine. Will be interested on what they say.
How about Isuzu? I find it's better to go in person or call and talk to somebody when possible. E-mails have a tendency to get get ignored, missed or lost. Not always though. Some keep up on their e-mails. Hopefully you can get the parts you need easily.
Worth a try, the closest dealer to me is this place: https://www.conwaybeam.com/locations/buffalo-ny/ I guess I'd be worried that a truck engine is not the same as an engine for an excavator, especially the injector pump etc. These days, people at dealerships don't really want to go out of their way to help with anything other than vehicles listed in their current database as they are not going to want to be liable for any parts incompatibilities. However, if I was to overhaul this engine someday, I'd prefer NOS parts from Japan and not aftermarket from China... This place seems to be an Isuzu engine distributor: https://www.pennpowersystems.com/engine-remanufacturing.php However, they look like a corporation setup to deal with companies via service contracts and not a parts counter for individual Joe Schmoe's etc...
I think you need to find an industrial Isuzu dealer not a truck dealer. Two different divisions. Maybe a shop that builds generators with Isuzu engines. I don't think it will be that hard to find OEM parts. The engines were/are very popular. Hopefully the Hitachi dealer gets back to you. I just looked on Google under Isuzu industrial engines. They have a US head office in Michigan and list all their dealers. There looks to be some other authorized dealers too.
Yeah, I used that website to find the Penn Power Group website. Looks very corporate.
What does that mean? You're looking for parts so if they can get you the parts should be all that matters.
Meaning they are willing sell to an individual via credit card orders.
Why are you thinking repower and re-pump? Is it all shot to heck? Sounds like get some parts and fix the fueling issue, and keep checking it out.
Is that a problem? Maybe there's a local shop that could bring the parts in but they could cost more. I wouldn't be thinking everything is shot just because the engine needs some work.
It was mentioned early on in this thread the the engine and pumps for this machine are obsolete and that a re-power and/or re-pump would be more economical. I helped my brother get a Koehring 6608 operational recently and we actually had to take a heat damaged variable displacement main pump drum to a local machine shop to get it re-faced and have a new wear plate laser cut out of 4140 that was thicker than the original and then heat treated and ground so the overall height of the assembly was the same as the non damaged assembly. It was impossible to find parts for the main pumps. We could not even find a parts manual for the pumps. At this stage I'm not saying the engine and pumps are no good in this UH122, I am just trying to do a pre-project evaluation to see if parts for this machine are as impossible to get as that Koehring. It does seem like there are parts available for the E120 engine, at a minimum, Chinese aftermarket from places like FridayParts. Investigating whether or not I can get OEM I think is worth it as I prefer OEM to China etc. I have not done research on the pumps yet, I only know that the parts manual I bought for the UH122 does not break down the pumps and I have yet to find a parts manual for those. All the hyd pumps, motors and vales on this machine are Kawasaki and they do not have parts breakdowns in the manual I bought.
OEM engine parts are likely readily available. You really need to get in touch with a long term Hitachi dealer that knows the UH machines from the 80's. I would think there's a lot of them in equipment salvage yards too. They were the most popular machines by a big margin back in the day.
Yes, I think this is the key. I have a 1971 Pettibone Extendo 88 that is quite impossible to get parts for, I did find a place that has experience with those machines: https://www.landmarkequipment.com/products/pettibone/ However parts are still impossible to get, you have to get lucky finding machines that are being dismantled. From my understanding there would not be a Hitachi dealership that knows the older machines because John Deere took care of the North American distribution back then and they just stopped doing that just a few years ago? I have been following this guys EX120-2 project to see what kinds of problems he has with parts: However I think he will have an easier time getting parts for an EX machine as opposed to a UH machine...
The UH machines were extremely popular and I don't think all Hitachi machines were part of the deal with JD. For sure the UH20 wasn't. I'd think there must be some dealers from back in the day still in business. Even when the JD deal took effect the many UH machines still operating needed parts and service. Although newer, smaller machines like the EX120 weren't nearly as popular as 200 size machines like the UH122.
Good morning i have a uh123 parts are hard too find you have too contact vendors in China they have what I needed for the final drive which I rebuilt one side check that oil don't run it without checking them and any leaks stop.I now have the drive motor apart that's the next rebuild.Diesel Dave helped me a great deal with his knowledge
I have the uh123
In regards to the Isuzu engines models, the core of the engine would have to be the same with the difference between industrial and truck being the fuel system. IMHO pistons, rings, bearings, valves and seal kits etc would be the same. Thepumpguy should be able to enlighten you about the fuel system as to whether it's rebuildable or replaceable off the serial numbers on what you have. You should be thankful youre not trying to restore a UH12 with a Hitachi engine, parts for those are like rockinghorse ****.
I have a UH143/UH12 and it has the Hino engine. Was made for the euro market in 1985. I had it sent to New Jersey then to Staten Island. Was brand new, grey market, not available in USA at the time. Mine came from Holland, German writing on interior warnings. That Hino is one of the best running engines I ever owned, and so quiet. Nick
I had a Hino truck. Very cold blooded but incredible fuel economy. 14 or 15 mpg on a 4 ton dump truck.
Yes my hino is so quiet the uh123 is a back up great demo excavator a beast hard too find one I'm glad I purchased it
I almost have all the parts/service/operators manuals I need. Mostly found downloadable pdf's, but had to buy a few paper copies from eBay. Unlike my brothers' Koehring 6608, it seems I can find UH122 main pump parts from places like FridayParrts in China: KVC925 Hopefully I don't need any engine or pump parts, just seal kits...
Good glad you found them.yup china
One manual I cannot find online and that is for the hydraulic components parts lists. I can find one for a UH10-2/UH121: UH10-2/UH121 I can also find one for a UH10-7/UH123: UH10-7/UH123 However I cannot find any for UH122 specifically. Were there any UH10 dash numbers between a -2 and a -7 that is the equivalent to a UH122? It seems like my machine is between those. I'm tempted to just grab both of these manuals and hope they cover any part numbers I'd need to search for.
Double post
What’s the part number listed in your book for one of the complete main hydraulic pumps ?
4100781 PUMP; PLUNGER
Key 23A part # 4089122 is broken down at AVspares. https://avspare.com/catalog/hitachi/156:uh123/ab1fb6de-aa09-4b12-a6f9-3a726a51ccaf/ .
I guess I am a bit confused by the item numbers on the diagram. Item 23 the QTY is 2, while item 23A the QTY is 1 (machine has 2 variable displacement pumps, seems like QTY for item 23A should be 2). Is that saying the 4089122 pump is a replacement for the 4100781 pump? Then item 23B is not even a pump but some kind of internal valve? Also on AVSpares under compatible equipment models for the 4089122 pump it lists UH121, UH123, UH171 & UH081, but not UH122. Thanks for finding on AVSpares, I have used that site in the past to find part numbers. I think what I will do is buy both the hydraulic equipment manuals for the UH121 & UH123 and hope for the best when I get into the UH122 pumps & valves for inspection if/when I get going on this machine. Seems like the UH122 is an odd duckling for some reason...
Key 23 part # 4100781 is the number for the complete pump. Key 23A Part # 4089122 is the number for the pump without the regulator. Key 23B Part # 4100781 is the pump regulator.
Ah, I get it now, thanks!
Yeah, it's just when I click on any of those pages, the diagrams have a UH123 watermark at the bottom left corner. And my plan to buy the UH121 (P1719-H-5-1) and the UH123 (P156-E1-1) equipment parts manuals didn't really pan out, both pump setups look very different than the UH122: But in the UH123 manual I downloaded (156-E1-1) only shows a single pump that looks fixed displacement? I will use AVSpares for now, but I'd really like to find the P1719-H-6 manual someday.
The dual pump setup for the UH123 is in a horizontal arrangement like the UH121: https://avspare.com/catalog/hitachi/156:uh123/eda1268c-33fe-4238-9dfc-965de33ff76f/ I guess I'll deal with all this when the time comes to find seals. Was just hoping to get all the manuals ahead of time.
UH122 is an odd duck for sure. I saw your pic of the Staffa type swing motor, bet that will have some torque !
Do you know if that motor should have a tag on it? I took some more pictures of it this morning but only found casting numbers. The brake valve had a tag. It's driving me a bit nuts that AVSpare never lists UH122, always UH121 & UH123: https://avspare.com/spare/hitachi/4089121/ Also was wondering if the control valves had tags on them? Would those be Hitachi or Kawasaki? https://avspare.com/spare/hitachi/4166715/
The swing motor tag may be lower down on the housing near the mounting flange. Years ago I was up close and personal with the control valves on a similar vintage Hitachi WH073 wheeled excavator. The control valves had manufacturers tags but I believe they were not Kawasaki or Hitachi.
UH122 was the most popular model at least in Canada. I knew a guy that owned a couple of them as well as a UH121. He said the only difference between the 121 and the 122 was that the 121 didn't have live swing. It means you can't swing while traveling. I'd guess the 122 had an extra pump or one of the pumps was higher GPM.
I guess it makes sense now why the swing motor is so different. They must have ultimately found a "more reasonable" motor solution for the UH123 swing motor. This Staffa radial engine looking pump looks expensive to mess with as opposed to a fixed axial displacement motor. Maybe this is all Hitachi had available to them at the time. I know my CAT 225 built in 1978 almost 10 years before this Hitachi has a similar setup, you can swing while tracking, Hitachi needed that same feature. Five pistons & cylinders vs. a piston drum and plungers. It looks like the UH122 has 3 pump mounting locations, but the small 3rd gear pump has two chambers. One chamber is for the swing and boom up assist (I assume boom up only), the other is for pilot pressure.
I doubt Hitachi would have had issues getting what ever swing motor they wanted. They design a machine to make 100's or 1000's of them. They have different models for different markets or price points. They could certainly update models though.
Maybe. CAT designed all their own engines pumps and gearboxes where it seems Hitachi was reliant on other manufacturers.
Hitachi gave the excavator industry the biggest shot in the arm ever when the UH series machines came out. Everybody else was playing catch up. Cat was sourcing excavators from Mistbishi around that time. You hardly ever hear about the Cat EL machines on here. They weren't nearly as popular as other Cat models over the years. I remember reading an ad in a construction magazine in the 80's that said 1 out of 4 of all excavators sold (at that time) was a Hitachi. Hitachi has came up with a lot of innovations and new technology in excavators. It shouldn't be hard to find parts for a UH122. It was one of the most popular excavators ever made.
Leemar Excavator Components Spare excavator parts, equipment & hydraulic shop. Leemar is a global supplier of new & used excavator parts. We ship across Canada, and USA. New, Rebuilt, Used Parts. Contact Us Today. www.leemarexcavatorparts.com Try these guys . They deal in a lot of Hitachi stuff.
That looks like it could be a great source for parts and info on older Hitachi machines.
Thanks, I'll check them out. Unfortunately they are about as far away from me as they could be on the North American continent.
Leemar said they would not be able to help me with any parts, not even seals. Ouch. Could not help with any manuals either it seems. I should be able to match up seals myself, unless there are some very special seals. Have to wonder how many UH series machines are left sitting in various stages of dismantle in North America. Maybe most have been scrapped or sent overseas. Hopefully I don't need any hard parts for pumps & valves.
I also just realized the service manual I have is only for the HYD equipment, so no Car Body, UC, Electrical, Boom, Stick, etc. Found one on eBay for a UH123: UH123_Service_Manual But coming up blank on one for a 122. If anyone happens to own one and either wants to sell it or at least get me the part number off the manual, that would be awesome.