My serial number is NAS00177 and I am having issue with the pressure setting on the thumb circuit. The rest of the hydraulics work as they should but when i go to the setting for the hydraulic pressure for the thumb, the max I can achieve is about 600 psi. The pressure can be lowered and is noticed but is easily collapsible. I'm assuming its previous life that it had some other attachment only on it as there's an extra switch and wiring out to the end of the stick. Any help is appreciated. Thanks
Are the thumb cylinder internals ok?
Haven't taken it apart but it doesn't appear to weap anymore then usual I would say. It's a GENTEC brand which is fine with me (came with the machine), other than I can't get it to be useful. I have contacted a cat service technician regarding this issue and the information he gave me allowed me to get into the configuration area (or at least one of them) for tool setup. The max pressure I could get was 4000 kPa which I translate to about 580 psi?
Put a gauge on it? Maybe extend it out fully, cap the lines and see if it holds?
No I haven't yet. Still a little new to the machine. Had a 315DL before that the cab caught fire on and this was my replacement that I purchased and have been having hire hands moreso running it. But we all agree that the thumb is more decoration then useful
There is valves on it to and when closed to my memory, the cylinder stays put. Are you aware of any different settings on the display to adjust? That's where the cat tech was aiming me to.
I have no idea on Cat. I have to set the pressures on my Case. Put them where I want and no issues. Get a gauge on it to verify pressure, and I'd guess much beyond that is gonna require a visit from a higher power, unless you can get into the diagnostic menu?
Check for manual adjustable circuit relief may have been set low to prevent damage to the thumb.you may be able to increase it there. Usually the circuit relief’s are set higher than the main relief but on the thumb circuit they can be set lower to Allow the thumb to retract a little bit with the bucket
Initially when I got the machine, the thumb was very slow at extending, and rather fast at retracting that it seemed like it would slam open. I managed to adjust those pressures through the screen, and to my understanding, that's where the adjustments are on this model of excavator? That being said, I'm no expert on it either.
I guess I'm also looking for a hydraulic and electrical schematic for the auxiliary circuit please.
Can you send me pictures of the thumb and also the plumbing on it. Like where the lines go to etc. you could have a simple relief valve issue or solenoid not working etc. there should be a small solenoid valve box above the main pump that feeds the thumb or better just follow the lines and take pictures where it’s connected to in the main control valve etc
Pics of the plumbing on stick? Sounds as if it is plumbed to a medium pressure circuit. Picture of screen where you can only set to 600psi?
I believe the 580psl you are seeing is pilot pressure at the work tool pressure reducing valves. The different configurations depend how they combined the pumps or run single pump for each of the different function. Going to look through as built to see what specific hydraulic option your machine had to get the correct schematic/procedure Those factory settings can be adjusted or (calibrated)
Not having any luck matching what system your machine runs according to that serial number This is what will decide on what schematic and adjustment procedures you would need to follow.. System five is the ideal set up to run just a thumb. Looks like all the calibrating that can be done is through ET so you would have to plug into it. The valves and plumbing Where the aux lines come to the back of the boom would probably identify what system the machine is equipped with And whether or not it would have any other circuit relief valves. System five does not have any other circuit relief but the line reliefs at main control valve auxiliary ports. Would not mess with those unless you can get into service mode (need Passcode) on your monitor to properly set those when that thumb was slamming open it may have been on a work tool settingThat was combining pump flow on that retract side. Thumb should operate on single pump two way setting Definitely would verify the cyl is 100% no DTCs indicating any issues with any of the PWM or coils or wiring.May have to bite the bullet and have the dealer come out
Thanks everyone for the replies. I will get some pictures soon, I'm just not near it and am trying to do some head scratching for when I get a chance to put it into the shop. I feel it is running on the medium pressure circuit too.