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Hitachi ex120 swing motor leaking (what else to look for?)

shelbyk7

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BA34656A-6BF2-4887-BD90-CD51649ECDF8.jpeg 72011C5D-FF13-4997-A8E5-E8819DD60BFF.jpeg Was losing a lot of fluid at swing motor so Pulled the swing motor to replace seal

Is there anything else to check for once I’m in there?

also, is there more than one seal tht could be the culprit?

attached picture- is the seal #35 all I need?
 

uffex

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Good day
I recommend you check the swing bearing movement, this can cause the bearing to fail in the bottom of the swing transmission. Not sure what has happened to your thread, strange attachment maybe gone wrong.
Kind regards
Uffex
 

Tones

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As Uffex said. A failed seal is usually a symptom not a cause.
My guess is #35,37, 21,20.
 

shelbyk7

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Okay pulled swing motor and #35 seal is bad

i had ordered a swing motor seal kit but it did not have this seal, had a much smaller seal with other orings (pic attached)

is there anything else to look for while it’s out? Best way to check the bearings? Will it be obvious?C7B078FE-27FF-424E-967B-8C507FE183BD.jpegD6B3435B-8C89-4DD2-A332-8EF4360A3DFB.png74026819-6C8C-4CC1-8128-AA0B0F412099.png
 

shelbyk7

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So what are some symptoms of needing seal kit for the swing motor? Trying to see if I need it

Do they have “kits” for the gear box?

I purchased a new seal for gear box what else should I get?

They sent you a seal kit for the swing motor instead of the swing gearbox
 

shelbyk7

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Well I’m not entirely sure if hydraulic is in gearbox,

i pulled it because the gear oil kept running out and would bogey low on dipstick

also when I pulled motor and gearbox (all together) a lot of water is in the turn table

i loosens a couple bolts underneath it but still water standing ?
 

Kobelco ireland

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If the gear oil is leaking out of the gearbox then you need the big main bottom seal(part #35 in parts diagram) and you need to check for play in the bearing. The water in the grease bath can be drained from underneath the machine through an opening in the frame covered with a small rectangular plate.to access this plate you need to crawl under the machine between the two tracks and look up through the hole in the bottom of the under carriage towards the turning joint
And you should see a small plate held on with two bolts.
 
Last edited:

shelbyk7

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Checking for play in the turntable, do bearing #21 and #20 go out very often?

If the gear oil is leaking out of the gearbox then you need the big main bottom seal(part #35 in parts diagram) and you need to check for play in the bearing. The water in the grease bath can be drained from underneath the machine through an opening in the frame covered with a small rectangular plate.to access this plate you need to crawl under the machine between the two tracks and look up through the hole in the bottom of the under carriage towards the turning joint
And you should see a small plate held on with two bolts.
 

uffex

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Good day Shelby
Much depends on care external causes of failure includes striking electric cables, over bucketing, water ingress. Checking will give peace of mind that the gearbox repair will not fail for that reason, additionally to knowing how much worn the bearing is at.
Kind regards
Uffex
 

shelbyk7

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Thank you

honestly, I do not have the means to remove the cab completely to change the giant roller bearing. Unless it was absolutely terrible I don’t think it will be changed unless I spent some time gathering some equipment to do it. I’d like to know if I’m in spec though so I will try to get that done

in regards to water in the belly, the center joint which has a rubber cover around it, is not sealing to the metal really well. (Picture below ) can that cause water to get into any spots it shouldn’t be?

I had something else come to mind

on the left joystick , a wire has been cut or broken and not repaired. (Picture below)

also a (black w/ yellow stripe)wire running up side of the boom (left side if sitting in seat) also has been torn off. What is this for?



Good day Shelby
Much depends on care external causes of failure includes striking electric cables, over bucketing, water ingress. Checking will give peace of mind that the gearbox repair will not fail for that reason, additionally to knowing how much worn the bearing is at.
Kind regards
Uffex
 

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shelbyk7

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So I got the swing motor seal kit and didn’t occur to me at the time that it wasn’t considered all one piece with the gear box

So now im needing all of the orings on the gear box, I did order the big seal on gear box already

I am not having luck finding a kit with these orings? And having hard time finding them at all

this attached drawing is of a ex200-2 but it comes up when I select ex120-2

so I need all orings in the diagram

anyone have idea of where to get a kit or where to order individually tht would come in quickly ?
 

shelbyk7

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How much play should the shaft #3 in diagram have? Trying to determine roller bearing is okay or not

The splined end of shaft (closest to bearing moved .024”

pic below
 

Attachments

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uffex

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Good day
If I have followed the illustrations correctly, the 0.024" you are recording is at the output of the motor. Unless hydraulic fluid is filling the transmission, there is little to be concerned. The actual measurement I do not find alarming.
Kind regards
Uffex
 

shelbyk7

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Thanks I wanted to be sure while it was apart

Good day
If I have followed the illustrations correctly, the 0.024" you are recording is at the output of the motor. Unless hydraulic fluid is filling the transmission, there is little to be concerned. The actual measurement I do not find alarming.
Kind regards
Uffex
 

shelbyk7

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Can this be washed out with a hose by chance? Kinda nasty in there , any best practices,?

If the gear oil is leaking out of the gearbox then you need the big main bottom seal(part #35 in parts diagram) and you need to check for play in the bearing. The water in the grease bath can be drained from underneath the machine through an opening in the frame covered with a small rectangular plate.to access this plate you need to crawl under the machine between the two tracks and look up through the hole in the bottom of the under carriage towards the turning joint
And you should see a small plate held on with two bolts.
 

uffex

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Good day
I would suggest dilute what is left after draining with some parrafine or similar, if you can hire a hot pressure wash to clean up.
Kind regards
Uffex
 
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