Hitachi Ex120 Problem

[willie59]

If you're replace the entire PPC valve assembly, it's pretty easy, ports are marked on the bottom. Just make sure you don't switch the location of the fittings, sometimes they are different. If you are just replacing components of PPC valves, would help to know exactly what you're planning on doing.

In either case, the most time you'll spend will be getting the consoles apart on left and right and getting the PPC valves out. Kinda cramped and tight quarters inside the cab of an ex working on those things.

 

[kuriwao]

I was just wanting some instructions and a picture of all the things that might come out and bite me and get lost some where in the cab thanks for your reply cheers Brent

 

[willie59]

Well, if you are simply replacing the entire PPC valve unit, not much will go awry. But, very important, mark the orientation of the valve, how it's mounted, like Front Side. If you turn those things just one quarter turn upon re-install, it's not going to work proper. And make certain you don't switch around the fittings in the bottom of the PPC valve where hoses connect, sometimes those fittings are different.

Aside from that, It's just a matter of removing console panels and such to get to the valve to service it. Be sure and remove the joystick handle from the PPC valve stem before removal, just easier to do when it's mounted solid in the framework of console. You'll have to disconnect wire that goes to horn button or throttle button so you can spin the handle around and unthread.

If you're going to take the PPC valve apart to reseal, then there are a number of gizmos that can go flying to parts unknown. Here's a thread that shows what's inside those things. This from a Case 9050B, but these things are very similar is design and setup.


https://www.heavyequipmentforums.co...g-a-leaking-joystick-control-valve&highlight=

 

[rgl726]

I was just wanting some instructions and a picture of all the things that might come out and bite me and get lost some where in the cab thanks for your reply cheers Brent

the easy way for this is to remove the cab

 

[ewtop123]

I have a question regarding the hitachi ex 120-3 i bought the dr.zx for it n i can't find the connection for it i located one where the dash it but im unable to connect or make connection i sometimes get connected to icf thats about it can i get a pm from someone who knows how to use the dr.zx palm thanks

 

[kokoy]

i have an ex 120-2 machine, it gets slow after 40 mins of operation especially traks and swing. i need help, thanks..

 

[pemolitor]

Thank you for your help rgl726. I Took the machine to the local Deere/Hitachi shop and had them run diagnostics on it...They determined that the pump or the manifold has an internal leak. The pump is new so I'm guessing it's the manifold. I need to find a new manifold or rebuild the existing one. The guys at the shop suggested against rebuilding. I'm running it with the dp sensor unhooked to get me by till I can find parts to fix it. Will this hurt the machine? It runs well like this just smokes a little more.

 

[Andre-1]

Thank you for your help rgl726. I Took the machine to the local Deere/Hitachi shop and had them run diagnostics on it...They determined that the pump or the manifold has an internal leak. The pump is new so I'm guessing it's the manifold. I need to find a new manifold or rebuild the existing one. The guys at the shop suggested against rebuilding. I'm running it with the dp sensor unhooked to get me by till I can find parts to fix it. Will this hurt the machine? It runs well like this just smokes a little more.

I have the same problem you experienced pemolitor. There is a clicking noise in the pilot hose and the machine loses power when doing combined functions. Which pump did you say had the leak? The pilot pump or main pump?

 

[pemolitor]

My pumps are new. We think its in the manifold. I'll know more next week.

 

[Andre-1]

what manifold is this exactly? i guess u mean the main control valve

 

[pemolitor]

Yes, the main control valve.

 

[kokoy]

i have a machine ex 120-2, the arm extension is out of control, sometimes no movement, i check the solenoid valve, its sticking, i need help, thanks in advance.

 

[jaytech]

Great site! i bought an ex120 and only after getting it home discovered it would bind up after 20 min. i did extensive reading on this site and swapped the displacement solenoids.
that did not help so i felt i had a sensor problem and decided to to have a deere expert check it. diagnostics showed a bad angle sensor. after a quick r/r she running great!
my thanks to all. keep on digging

 

[Andre-1]

have you found a solution pemolitor?

 

[rgl726]

Thank you for your help rgl726. I Took the machine to the local Deere/Hitachi shop and had them run diagnostics on it...They determined that the pump or the manifold has an internal leak. The pump is new so I'm guessing it's the manifold. I need to find a new manifold or rebuild the existing one. The guys at the shop suggested against rebuilding. I'm running it with the dp sensor unhooked to get me by till I can find parts to fix it. Will this hurt the machine? It runs well like this just smokes a little more.

the symptom of bad or unhooked DP sensor is hydraulic hissing. because the pump keeps on banking even without demand or sticks in neutral.

 

[Andre-1]

My pumps are new. We think its in the manifold. I'll know more next week.

Pemolitor have you discovered the problem or found a solution yet?

 

[pemolitor]

Pemolitor have you discovered the problem or found a solution yet?

I haven't found the problem yet. I've just been running with the DP sensor unplugged.

 

[Andre-1]

I haven't found the problem yet. I've just been running with the DP sensor unplugged.

I found the problem. The pressure in the pilot system and on the compensators was low. correct values 512+/- 15 PSI pressure reducing valve, 750 + 140- 0 PSI for Pressure on arm out pilot cap. these are for a 490E excavator. try teeing into the line from the pressure reducing valve and the arm out pilot cap line and check the pressure. I added shims in both the pressure regulating and pressure reducing valves to increase the pressure as needed.

 

[pemolitor]

Can you post pictures? I'm not sure were all the components are as I don't have a manual.

 

[tool_king]

pemolitor
I can email you a manual if you need it.What dash number is you machine?Do you need a parts and service manual.