I have just replaced one of the backhoe hydraulic lines on my JD 790 (backhoe model #7). I was looking for instructions in the manual as to how to bleed the line(s), but all that I can find is something that says "Lower stabilizers to the ground. Operate control levers to move all cylinders several times until backhoe runs smoothly." I have never had to bleed lines on any hydraulic system, but I thought there was more to it than what the JD manual says. Any help would be appreciated.
Bleeding hydraulic lines on JD 790
- Thread starter satchvet
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Gatorboy
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Someone can correct me if I'm wrong, but I don't believe hydraulic lines need to be bled. This past spring I replaced 3 hyraulic lines on my rotary mower (each about 15' long) and it operated fine without doing any bleeding.
RobS
Super Member
To word it differently, yes the lines do require bleeding as they will have air in them. Fortunately, they are pretty much self-bleeding so as you cycle each cylinder the trapped air will work its way back to sump naturally. You may notice some sluggishness/sponginess in the cylinders until the air is out. It should only take a couple of strokes to be all set /forums/images/graemlins/smile.gif
beenthere
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Just extending the cylinders to their limits a couple times will take the air out and no bleeding required.
LBrown59
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How do you get pressure out of the line so you can install the new one? <font color="purple"> </font>
LBrown59
Welcome to TBN.
To get the pressure out of the lines to install new hyd. hoses, with the tractor turned off, lower all hyd. equipment to the ground. Cycle all controls in all directions until there's no movement in any attachments (FEL, BH...). You can now remove the hose(s).
Welcome to TBN.
To get the pressure out of the lines to install new hyd. hoses, with the tractor turned off, lower all hyd. equipment to the ground. Cycle all controls in all directions until there's no movement in any attachments (FEL, BH...). You can now remove the hose(s).
Boulder_Hill
New member
LB,
Also be aware that when you take a line off, if the cylinder is at an angle (as in a FEL or back hoe), all that fluid in the cylinder can come running out!
-Lloyd
Also be aware that when you take a line off, if the cylinder is at an angle (as in a FEL or back hoe), all that fluid in the cylinder can come running out!
-Lloyd