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Hydraulics are not working!

1690 Views 8 Replies 5 Participants Last post by  medmpmpn
I have a JD 850 and yesterday the hydraulics on the front end loader and rear lifter started acting up. Yesterday they were jerky and going up very slowly. Today they are not working at all. There is also a hissing sound coming from the mid section of the tractor but it's doesn't appear to be a hose leak because there is nothing spraying out. Sounds like a loud rapid sstsstsstsstsstsstsst. The reservoir is reading more than full and after letting the tractor run a little bit and trying to work the front end loader I took the cap off the hydraulic reservoir and there is a lot of bubbly foam on the top of the fluid.

Looking for advice on how to trouble shoot or suggestions on what could be causing my hydraulic problems.
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The reservoir is reading more than full
My first move would be to get the fluid to the proper level.
It sounds like your implement hydraulics are going into bypass. Do you perchance have a Power Beyond setup on this machine? If you move SCV control handle for the loader does that sound from the middle of your machine change?
I'm not sure if I have a Power Beyond setup or not. When I pull on the control handle there is no change in the sound.

This issue seems to have come on pretty suddenly, before yesterday things worked as they should. A couple other items that may help:

1. I still have power steering
2. I can still shift into gear
3. I have had a small leak coming from the box that is connected to the control levers. There is a round fitting on the top of it that sometimes leaks when I use one of the control levers.
4. model # of the 850 is 004740
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I'd dis connect FEL to try and Isolate this issue.
Then try 3 point lift.

I'm sure this has happened before...
Take notes and try a couple things.

FEL valves can malfunction....Sadly none of these items in the system are cheap if even avl. Do you have the Service Manuel..??
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Thank you for the advice. I am going to started with a hydraulic filter and fluid change. It hasn't been done since Ive owned the tractor so i figure thats a good place to start and also needed.

The fluid came out two colors: the color of charcoal and the color of grey milk. Separating as it came out and still had some bubbles. Does that just mean it's dirty or indicate something else?

Should I look at the screen while I have the system drained?
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Milky fluid usually indicates moisture.

Yes, clean the screen as well.
Should I look at the screen while I have the system drained?

As far as milky color and it coming out separated from the rest of the fluid tells me you had a lot of water in there. Maybe this is why the fluid level was high?

I would look for a point of entry where water could be entering the system. Is the tractor parked outside?
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Yes the tractor is parked outside. I have a small leak in the top of the box that the control levers connect to (SCV box?). The fluid comes out of a round port at the top of the box. I suppose water could be getting in there. It has rained alot here lately. I cant imagine that there is a lot of water getting in there but maybe...

The fluid level was high because I overfilled it thinking that it may have just needed more fluid to operate...stupid i know...

Anything else I should check / clean while the hydraulic system is drained?
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