• Thank you for visiting HeavyEquipmentForums.com! Our objective is to provide industry professionals a place to gather to exchange questions, answers and ideas. We welcome you to register using the "Register" icon at the top of the page. We'd appreciate any help you can offer in spreading the word of our new site. The more members that join, the bigger resource for all to enjoy. Thank you!

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

shelbyk7

Well-Known Member
Joined
Jan 3, 2022
Messages
63
Location
oklahoma
Okay, that’s what I was confused about, I thought you were saying paraffin, the wax and couldn’t make sense of it

i do have kerosene ,thanks

Good day Shelby
I would suggest make the best of what you have availible, normally the Parafine (Kerosene) will clean up reasonbly well.
Kind regards
Uffex
 

shelbyk7

Well-Known Member
Joined
Jan 3, 2022
Messages
63
Location
oklahoma
Getting ready to add fluids back into machine

Is there anything special I need to do? I drained pump and tried getting all the fluid and it because the fluid was nasty

put some in swing motor before installing it.

Anyway I Can put any in pump before starting it up?
 

shelbyk7

Well-Known Member
Joined
Jan 3, 2022
Messages
63
Location
oklahoma
Also. uFFEX

i rebuilt fuel pump, it had an electric in line when I got it

rebuilt it, would it hurt to leave the electric just to assist? Any diagram for how fuel lines and system should be routed?

Not sure if original owner bypassed the mechanical lift pump or not when went electric
 

uffex

Senior Member
Joined
Jan 23, 2012
Messages
4,464
Location
Lincoln UK
Occupation
Admin
Good day Shelby
I cannot be sure regarding third party fuel pumps however I have attached all the illustrations I have with regards to the fuel system. Pumps & Motors make sure you flood - bleed the body of the units before you crank the motor - run the engine at idle for a short time to clear any remaining air or ingress.
Kind regards
Uffex
 

Attachments

  • Isuzu 4BG1 FuelSys.pdf
    503.5 KB · Views: 2

shelbyk7

Well-Known Member
Joined
Jan 3, 2022
Messages
63
Location
oklahoma
So the electric fuel pump brand is-
“ Facet Posi-Flow”

Here are the specs, not sure what exact model is in mine but looking today . Is 10psi enough ?

Available Features

  • 12 inches minimum dry lift
  • 23 - 40 GPH
  • 1.5 - 10 PSI
  • ESD compliant
  • 1.5 amp average
  • Diesel Priming and Self Regulating
  • Light-Weight - Compact
  • Internal 3.5 amp fuse
 

skyking1

Senior Member
Joined
Nov 3, 2020
Messages
7,465
Location
washington
my early JD120 is about equivalent to a 120-3
The tub in mine was not a separate piece, it is all integral welded stuff.
I did not get pictures, but the swivel is mounted in a raised up area with a rim on it. The water may be sitting on just that upper area. I had a small amount that rained out on me when I pulled the swivel, but no signs of water in the main tub area where the slewing gear runs.
 

shelbyk7

Well-Known Member
Joined
Jan 3, 2022
Messages
63
Location
oklahoma
Thanks

i have found this sensor leaking onto the tracks behind the cab. Some kind of Pilot sensor? It’s kind of busted open and leaking at the break. Picture below,

Is this important for function? Or can it do without?
 

Attachments

  • 5A5522DC-A86D-4363-8BD8-F8A1A021C0B4.jpeg
    5A5522DC-A86D-4363-8BD8-F8A1A021C0B4.jpeg
    1.5 MB · Views: 15
  • 1566D953-8327-4F65-AA32-6C03ED2E7C34.jpeg
    1566D953-8327-4F65-AA32-6C03ED2E7C34.jpeg
    1.4 MB · Views: 13

shelbyk7

Well-Known Member
Joined
Jan 3, 2022
Messages
63
Location
oklahoma
That's hard way Jones to pull it and find out. I would tend to get one coming and err on the side of "putting it back how they designed it", rather than try the weight reduction program method.


Fair enough, i just had some panels off and doing maintenance when I saw it leaking pretty good amount.

Seperate of this thread is the machine was having some normal ex120 issues of jerky controls and saw this as I was doing some other stuff to it and was curious if this sensor would cause issues if it were bad

i appreciate all the help, first excavator and I’m definitely a rookie. It’s taken awhile to go through it and I’m just ready to get her going
 

skyking1

Senior Member
Joined
Nov 3, 2020
Messages
7,465
Location
washington
If you don't have records of it, I would suggest doing a full 2000 hour service on it. That's all the fluids and filters, coolant, check everything. Get a service manual for the procedure.
It's about 700 in parts and pieces but if you can't see where it has been done that is money well spent.
I cannot diagnose "jerkiness" as I have not experienced it, but it could be due to things like that leak on the pilot circuit, or plugged pilot filter. Getting things fresh and clean will eliminate those as the source of the problem.
 

shelbyk7

Well-Known Member
Joined
Jan 3, 2022
Messages
63
Location
oklahoma
Great, that’s what I’m doing at the moment

If you don't have records of it, I would suggest doing a full 2000 hour service on it. That's all the fluids and filters, coolant, check everything. Get a service manual for the procedure.
It's about 700 in parts and pieces but if you can't see where it has been done that is money well spent.
I cannot diagnose "jerkiness" as I have not experienced it, but it could be due to things like that leak on the pilot circuit, or plugged pilot filter. Getting things fresh and clean will eliminate those as the source of the problem.
 
Top