Hay guys, On my hitachi ex120-2 it’s leaking hydraulic fluid from between the swing brg. Is there an oring at the bottom of the swing motor that could be leaking hydraulic fluid?
Check your swing gearbox oil level (90 wt.), if it's ok then your rotary manifold is leaking and needs to be pulled out and resealed.
Are you losing hydraulic oil?
Gearbox is full. Yes leaking hydraulic fluid. When I refill tank I can see it seeping out.
It seeps out without running, no functions? If the gearbox is not overfilled, it's not the swing motor. I would have to agree with Excavator in that your turning joint is probably compromised.
Yes seeps without running. Rotary manifold. Turning joint. They sound serious. Is that a bigger job than just pulling swing motor?
It's a bit more involved. A little deeper in the machine. Its gonna be messy. While not familiar with your machine, I would look deeper. Pull all your belly pans, drop the plate that protects the center. Be careful, some of these can be quite heavy. Get yourself a case of brake cleaner. Hose everything down from the top down. You have to clearly identify where the oil is originating from. The oil that comes from turning joint going to tank has to go through the return filter in the tank. You stated you see oil seeping as you fill the tank. That says a leak lower on the supply or return. Pay close attention to fitting and flange below oil level in tank. Check edges and corners of the tank itself. While not common, hydraulic tanks sometimes crack . I would hate for you to swap out or reseal a turning joint just to still have a leak. Good luck and keep us posted on your findings.
Thanks so much funwithfuel, as long as I don’t have to remove upper section from turn table it’s doable.
Hey guys, I got under the machine and saw that there is no way that the fluid is coming from the center joint. So if it’s not coming from the swing motor it must be from spilt fluid on the turntable. I hope soo. But why don’t I see it when it rains? I’ll keep an eye on it. Now I’m more concerned about why it bogs down under a load. Already changed fuel filter and cleaned screen filter. I think the boom solenoid valve is acting up now but is there a solenoid valve that would create the bogging down problem? Like maybe the pilot relief valve?
Does it blow black smoke while bogging down, or no smoke?
I didn’t even notice if it blew smoke when it bogs down. I will check, thanks Delmer
Delmer, Yes it does blow smoke when it bogs down. What does that tell you
Don't worry about the fuel system, it's not starving for fuel if it blows darkish even smoke. White or irregular smoke is a different story. The engine is overloaded (not underfueled), time to look at the hydraulics.
Thanks Delmer, I Would call it gray smoke That gets darker just before it stalls. Where would you start looking in the hydraulics I already changed the fluid and new filters.
Have you checked your air filter restriction? Is your turbo spooling up? Does it support bucket curled over relief. You said bogging earlier now say stalling. Is it stalling out?
It will stall if I don’t relieve the joystick. Air filter and pipe are clean. I don’t know what you mean by turbo spooling up or bucket curled over relief.
When you curl your bucket in or out to the end of cylinder and hold it. That is when the relief kicks in to prevent overpressure on the circuit. Typically a bucket function only uses one pump. Trying to determine if engine has enough to support one pump fully loaded. Turbo spooling is when the turbo is loaded, it builds boost at the intake manifold, if you have no boost, the engine cannot maintain rpm to support pumps. If you listen carefully you can hear it whine as the load increases.
First follow FWF and Delmers suggestions and make sure your engine is operating properly. Maybe post a video of the machine stalling? I think the -2 machines have the electronic hydraulic pump on it (maybe post a picture of the pump top). If it stalls fairly quickly and has the pump I think it has then check your pump and valve controller fuses (the ones highlighted in the attachment). I would check all fuses just in case. If fuses are all good then one of the solenoids on top of the hydraulic pump could be bad (there is a lot of other variables with the electronic controlled pump that could cause stalling).
Hay again guys, I really appreciate all the input you’ve been giving me. I started with the fuel system and found the banjo bolt screen. Boy it was filthy. Then drained the tank and boy that was filthy also. Ran out of daylight before I finished but thinking/hoping that’s the problem. Let y’all know tomorrow. Thanks
Damnit the fuel screen wasn’t the problem. Im glad I cleaned the fuel system but I just found a blown fuse. The one for the ec motor. Replaced the fuse and it blew as soon as I turned the ignition switch back on. Now how do I figure out where the short is?
Bigger fuse, look for smoke. Lol just kidding. Start at the protected components. Unplug them, replace the fuse and see if it fails. If so move further down to harness connections. Look around for where cabling goes through bulkheads and around corners. Look for pinches, chafes and burns. For some reason guys love to put grease guns and shovels in the battery box or the pump room.look for damage there as well. If you have serviceable diodes in the fuse panel, check those as well for shorts
Lol you literally mad me stop and reread that first sentence. Sounds like trying to find a needle in a hay stack. I’ll try thanks.
Disconnect your EC motor and see what happens, then start working your way towards the EC. Never disconnect any component with the key on, while I have occasionally done this by accident and haven't had a problem, you can blow your EC or PVC by doing it.
Thanks for your reply mg2361. Is that definitely the fuse box for my hitachi ex120-2? Because I don’t have the lid for it. And can’t find it in the manual. It is a gray market machine. Here’s what’s happening. As soon as I turn the key on the fuse blows. Third one from bottom on left. According to your diagram it’s for the ec motor fuse. So I disconnected the ec motor and the fuse still blew. After checking some wires I decided to plug ec back in and unplug the pvc. Now Fuse does not blow. Is it definitely the pvc?
My information is from a 490E Deere which is similar to 120-2 Hitachi so I am not 100% sure it is the same. If you are blowing the F3 EC motor fuse with the EC motor disconnected then the problem could be the wiring to the EC motor or the engine controller itself (see attached). It could be the wiring from the relay to the ECU as well (the load side, not the control side). Which controller did you unplug, the top one (Engine controller) or the bottom one (the Pump and Valve controller)?
I unplugged the bottom one the pvc and with top one plugged in the fuse doesn’t blow.
A 490E is the same as a 120-2&3. The main difference is Deere uses a Deere engine and Hitachi the Isuzu but the EC motor wiring ect. should be the same. Is this a 1 amp fuse that is blowing?
Like Excavator, I need to know what amperage was the fuse that is blowing (if in fact the correct amperage is in there to begin with)?
It calls for a 1 amp fuse but has a 5 amp. Most of the fuses are 5 amp
In the words of Charlie Harper - There it is......!! In what world does a 5A fuse replace a 1A because the 1A keeps blowing..?
Lol. I get your point Nige and those fuses were in there from the day I bought it. I’ll change them all but I believe the 1 amp fuse will blow also don’t you?
It will definitely blow. Your problem appears to be more major than was at first thought if it needs a fuse of 5x the original designed rating to stop it blowing under normal circumstances. The fact that someone put 5A fuses in everything doesn't make it right.
So it appears my short is somewhere between the ec and pvc
Is there a way to test the pvc? Red Led flashes on both ec and pvc
Yes there is a way to test them but it's a bit complicated. If your red lights are flashing there's a pretty good chance that they are not the problem. The F3 fuse is the EC motor relay circuit. Down below the EC & PVC and forward towards the seat is a row of relays. I will have to check which one is for the EC motor. Do you have a service manual? If not, it's looking like you will probably need to get one.
Thanks excavator, I do have a service manual. I found the relay on the right side for ec motor. Had corroded wires. Repaired them but didn’t help.
Today I swapped Ec relay and engine stop relay. Ec fuse did not blow. Didn’t have time to run it yet. Question: if relay was blowing the Ec fuse would that make the engine bog down under load? I know I can just run it to find out but it might be a couple days before I can get back to it. And should I take the horn relay or other instead of using the possibly burnt relay for the engine stop relay.
What happened?