Hitachi UH122

[361brock]

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.

 

[etd66ss]

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:

 

[361brock]

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.

 

[361brock]

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.

 

[etd66ss]

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.

 

[Acoals]

I'll bet those rails are going to be a bitch to get rolling.

Such a negative attitude. All those tracks need is a smile and a can of WD-40.

 

[361brock]

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.

 

[361brock]

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.

 

[etd66ss]

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.

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.

 

[Tones]

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.

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

 

[361brock]

When you fill the hydraulic tank, the stick should be fully extended with boom down & bucket fully curled in for proper hydro level.

 

[etd66ss]

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?

 

[361brock]

Is the key round like the old ace lock keys on car alarms from years ago?

 

[skyking1]

That's all good stuff, you got it barred past the rust ring pretty easy.

 

[Welder Dave]

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.

 

[etd66ss]

Is the key round like the old ace lock keys on car alarms from years ago?

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

 

[361brock]

Spray some WD40 in the slot & on the key, work the key in & out, maybe tumblers rusty.

 

[etd66ss]

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...

 

[etd66ss]

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

 

[Tones]

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.