Hitachi UH122

[etd66ss]

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/

 

[Diesel Dave]

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/

View attachment 304091
View attachment 304092
View attachment 304093
View attachment 304094


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.

 

[Welder Dave]

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.

 

[etd66ss]

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.

 

[Welder Dave]

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.

 

[etd66ss]

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.

 

[Welder Dave]

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.

 

[Tugger2]

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.

 

[Welder Dave]

That looks like it could be a great source for parts and info on older Hitachi machines.

 

[etd66ss]

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.

Thanks, I'll check them out. Unfortunately they are about as far away from me as they could be on the North American continent.

 

[etd66ss]

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.

 

[etd66ss]

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.