Primary Hydraulics 2010 Volvo EC140CL 3,100hrs

[just-a-mechanic]

Hey All!

I purchased a 2010 EC140CL excavator with 3,100 Hours (confirmed by me with the engine ECU hours) that has low pressure hydraulics. I purchased this because I believed I had the highest chances of getting a good mechanical machine and the price was right.

Hydraulic Issues so far:
-With the machine cold soaked, the boom will boom up and down and have some slight down pressure, lifting the machine up approx. 3-4 inches.

-When the hydraulic oil is at normal operating temperatures (50c `ish) the boom will not boom up unless the stick is all the way tucked in, then it will raise slowly. If the stick is extended it will not boom up. Also, at no time is there any down-pressure. This machine does not have "float" mode (floating boom") option installed.

-The entire machine reacts the same, not enough power to turn the tracks etc. I have noticed that the stick appears to have enough pressure, if I pull the stick in with the boom down, I can raise the machine, pressures are reporting around 2000 psi for both pumps if I remember correctly. Seems either boom up or down, only pump 2 was around 2000 PSI.

-The service tests, do not seem to provide further guidance on what I really need to do, as I am untrained and just don't know what to do

My Diagnostic equipment:
I have purchased the interface (VOCOM II) between the machine and my laptop and obtained PTT to read the ECC. I also have PROSIS installed (service manual). I am currently waiting on my hydraulic gauges set to arrive.

Tests Performed so far:
I have ran partial tests of the Proportional valves. I did not measure them directly but viewed what was reported on the main display in service mode.

Results:
From the Main display unit, in service mode, I can see Pump 1 and Pump 2 pressures and proportional valves commanded 400ma, to 700ma, and 250 ma idle. I have not measured them directly yet as part of the test is to watch the hydraulic pressures.

My thoughts:
I believe that a pressure bypass valve could cause this maybe? I need my gauges to confirm.
Also the regulators solenoids could? cause this as they control the demand and pressure of the hydraulic pumps.

The Machines hydraulic oil is full of AW46.
I do not appear to have frothing hydraulic oil or surges.
I do not have unusual noises or vibration.
I have not seen any contamination or metal particles of yet. But I need to pull out the return oil filter to make sure.

My background:
I have no experience in hydraulics on excavators or heavy equipment, only within helicopters and I am not proficient in hydraulics either way. So I come here as a student and ask that someone help me along the way to troubleshoot this machine.

So far, I have 25 years as a turbine technician and airframe (FAA licensed A&P mechanic). H60 Helicopter Test Pilot and Technical Inspector. Notice - nothing - of Heavy Equipment / Construction Equipment, lol

I am very good at mechanical and electrical items generally speaking, however this Machine is new to me and I am learning an entirely new way of doing things, from documentation to maintenance practice's. I am hoping someone can guide me along. Just do not assume I have enough common sense that surely I would have checked that! lol

 

[uffex]

Good day
Please check the pilot pressure first working temperature the PWM valves will not effect pressure only flow, when you raise the undercarriage or hold the bucket in the air do you have creep or does the hydraulics hold - it appears be have one pump circuit giving trouble but please check it out before you condemn the pump unless it shows signs that it has been tampered with.

 

[just-a-mechanic]

I plan to do this tomorrow. Right now I have disconnected one of the booms from the circuit. Since they share the same pressure to ensure I did not have the seals severely internally bypassing. I did find quite a bit of old seal and fibers from the seals in the return filter. I drained the oil and added fresh oil ~ well 25 gallons at least.

I have yet to see any meatal particles however I'm sure I am contaminated pretty good, from what I saw in the filter. Ill upload a picture later on.

Uffex,

When I check the other cylinder and perform the test I was already doing - I will check the Servo Pressure as suggested. However my manual does not give a goal of what pressure it should be. I guess we can assume something minus the bypass valve pressure. I do remember seeing creep at one point when at operating temp. I will have to start pulling circuits and checking for contamination, probably huh?

 

[funwithfuel]

On the information display, using the keypad in the right armrest, scroll to service (looks like an old pipewrench) press and hold the enter key. The display will show now entering service mode. Or something along those lines. Scroll up to hydraulics. You should see pump pressures, pilot pressures for each circuit as well as mA for the pump controllers. What your looking for is high pressure at idle. I'm guessing one of your pressure sensor has stuck or failed. It was common with the early ones.

 

[uffex]

Good day
FwF is correct you do not need pressure gauge other than that on the machine, you should be able to see error codes relating to any problems.
Kind regards
Uffex

 

[just-a-mechanic]

All,

I have no error codes related to the machine. So far as pressure gauges I do have a set now.

I did a proportional valve test and notice i am approx 250ma at idle and when commanded by the test laptop to 700ma both are reporting as 700ma and so on. my pressures indicated something quite low when I was testing this. However this is from memory and I rather re-test to be sure of what I am stating here.

I am assuming you mean pilot pressures you speak of the pressure coming from the actual controls that are generated from the Servo pump? I can not remember if they reported pressure changes or not. I will upload pictures and video if possible to the website, or at a min a YouTube video of what I find. Also, thank you for the tip on Service Mode, but I had already figured that one out

 

[funwithfuel]

Not good, but not the end of the world. The pic. Let's try and get into service mode. That will show you so much info. It takes a little poking around, you'll really like all the info available.

 

[just-a-mechanic]

Ok,

I have been testing the system out. The pilot Pressure is approx. 570psi and remains steady throughout. I did tinker with a proportional valve and tried adjusting it, I barley had any pressure rise even after sinking in the adjusting screw. I'll post some pictures and video's as well. I have entered service mode and messed around. I will post the link to the YouTube when its finished uploading.

I have something open allowing fluid to bypass or I have low flow is what im thinking. I defer to you gentlemen in the meantime.

I am all open to trying something out, or troubleshooting something else.

 

[just-a-mechanic]

Here is the video I shot today checking things out.

 

[funwithfuel]

That video was very helpful. You have good servo signals to your spools for boom and bucket. Low pressure, poor response.
How does the machine track? How does it swing. What about arm in/out? Right now I'm more concerned with travel. There's a procedure to "pin" the tracks. You take a solid piece of bar stock or a quality socket and wedge it between the sprocket and the track frame. As you travel against the pin, you should see max relief pressure since your travel relief is usually much higher than main. Please be careful and report your findings.
Lastly, do not , I can't stress this enough, DO NOT go turning screws or stems on valves you don't understand. You may cause a dangerous condition without meaning to. We'll help you get where you need to be, and we'll help you understand what you're doing and why.

 

[just-a-mechanic]

FWF,

It tracks straight but will not turn its self around, or really turn at all. The tracks has low pressure as well. The arm seems to work as it should, the swing seems ok as well. I will see if I can find something to use to pin the tracks with.

I understand the warning about messing with stuff to cause a bad situation. I will try to refrain in the future.

 

[uffex]

Good day Folks
If all is out of pressure I suggest that dead ending the arm + Boom if the pressure comes good makes the check valves a probable cause, if not check out the main relief valve.
Kind regards
Uffex

 

[funwithfuel]

With all the material packed around that hydro filter, I wouldn't trust deadhead on any function but travel. The fact that she doesn't want to turn says we got a piece of something blocking the oil to/from the regulators. I'm sharing the thought on the main relief. If main is weak, all are weak. Plus, in travel, raised pressure should be active. (Boost)

 

[just-a-mechanic]

FWF,

I’ve pinned the tracks and this is what I got. Similar to the previous video.

 

[TVA]

Next step is a main relief valve check.

Just yesterday I had to “redneck engineer” the port relief valve on the SK220 fresh from the auction - some dimwit took the valve apart, lost a spring seat out of it, couldn’t get it to work and hauled it to the auction!

Funny thing: you can actually buy that seat for $10 on Amazon.
Meanwhile the broken off ball end out of 6mm ball end hex bit will do the job!!!
Beats $800 for the new port relief from Cowin!!!

 

[funwithfuel]

Yeah, it's time to look at the main. I'll find some service literature to help you identify where you're going next.

 

[just-a-mechanic]

1 - 4 Hydraulics Main Control Valve

 

[just-a-mechanic]

5 - 8 Hydraulics Main Control Valve

 

[just-a-mechanic]

9 - 11 Hydraulics Main Control Valve

 

[just-a-mechanic]

FWF, and Others

Alright, Let me know if I should obtain anything further. I have OEM software and diagnostic equipment that I purchased for this machine.