Hello all, great forum here. I have used what I can that’s available for info but can’t seem to find an answer to a problem I have. Just the other day on my 580SE out of nowhere I think a relief valve got stuck open in the loader control valve because the motor stays loaded and I can hear a relief valve bypassing(I am touching no controls). The front loader now curls and moves entirely on its own without me touching anything, it does this slowly though. Given this backhoe is from 84 and the valve body has never been touched, I am going to tear down and reseal the whole control valve. I guess my question is, I have the large manual, is there a whole seal kit you can buy or am i going to have to buy each one separately Seems online the case dealer has everything. hopefully none of the relief valves need replacing since they seem to be around $200 a pop. Also I see where a pressure gauge goes to test pressure, does anyone know what size that is? Also since that’s for main relief how do you test the pressure of the bucket curl and lift reliefs? Thanks to everyone that’s on here for the help in advance!
Check the return to dig linkage first off, make sure it's not froze up. Then if that doesn't help then remove the end cap on bucket spool and check spring and detent housing.
linkage is good. A few years ago I disassembled and cleaned the linkage components because it did freeze up so I always make sure to lube it a few times a year after that. I will have some time this weekend to look into the spool and will let you know! Thanks
So I took the whole valve body off as I was going to reseal the whole thing anyway, since it hasn’t been touched since 84. Upon removing the relief valve. The white oring was broken. Then I get to the load checks. None of them even had an oring on them. Hopefully they find the filter first and not jam up a relief in the backhoe. Needless to say, that was probably my issue. Will circle back when new orings arrive. When it comes to the reliefs, is the general consensus not to tear them down and just replace the outer seals?
Yeah you can just replace o-rings on outside. But they’re not that difficult to tear down and reassemble.
I’ll tear down the main relief since theres a procedure in the manual for adjusting pressure with the backhoe itself, but the manual also states to test circuit reliefs that I need a handpump and test station. Can they be tested while in the machine, like can I just disconnect a loader hose and put a gauge on it that way? That was my hesitancy on tearing down the circuit reliefs.
You will only read main relief but you can set your main up and then you’ll read circuit relief but because you can do some damage.
ok so I got the loader valve back together and while the front loader functions do not move on their own anymore the engine is still loaded. Its as if the system is not bypassing when no loader functions are being used and staying under load. Is there an inline check valve or something that could be causing this? I would assume there is a recirculation part to this hydraulic system. Maybe something is clogged. Its quite odd because when I lift the bucket the engine load seems to go to normal until I stop moving the bucket up and it loads up again. Curling the bucket doesn't change much the engine stays loaded. Have you seen this before? End of the day I needed to reseal the loader valve anyway, so not bummed about spending time rebuilding that at least.
Don't know crap about an SE or if you even have quick connections at the back of machine for the hoe, but think I read somewhere similar issues with the quick connects being funky. Once again no clue, but may be something to check.
Were any pieces of it missing that may be causing your problem. Do you have the 580SE service manual ??
I am sure the load check orings were floating around somewhere in the hydraulics. I have good news though. I just randomly decided to play with the hoe controls as I had thoughts that trash was somewhere, maybe could dislodge it and as soon as I moved one of the stabilizer spools the loading instantly stopped and went back to normal. Must have been some junk there. Regardless all is good and back to normal. Thanks for the feedback on here.
You might consider changing the hydraulic filter. Then, cut the old one open and look at what may be trapped in the unfolded media.
Yeah I’m curious too, I’ll report back when I replace the filter if it was anything strange.
On my SE, if the filter gets filled with crap and is bypassing, I get the same issues. Only lifting the front bucket, it goes away while moving and starts up again as soon as I stop the loader valve. My left stabiler will do the same thing, not sure why but a filter change stops it. This happened a lot when my hydraulics were full of water. Did the purge and have had no issues so far.