Leaking valve on backhoe

phalynx · Feb 28, 2010

I have a new John Deere 485 backhoe mounted on my 4120 tractor. The side to side control valve is now leaking from the top of the valve whenever it is used. It becomes a steady stream of fluid. Can someone tell me what would cause it to leak? Would it be as simple as replacing some o-rings or is it a bigger issue. It only leaks when the side to side is used.

kennyd · Mar 1, 2010

If it's "new" it still under warranty correct?

Most likely, the seals around the spool have failed, most likely a defect when the valve was built. It should be a fairly simple repair.

phalynx · Mar 1, 2010

Kennyd, thanks for the reply. Are the seals, parts 12 and 13? If so, does the spool? (part 16, rod that moves up and down inside the valve) just come out after removing the top plate? I think I ultimately caused the failure. I think it happened when I swung the boom quick and smacked it into the side of the stump I was working on. I could see where a jolt like that would break seals.

kennyd · Mar 1, 2010

Yes 12 & 13 are the seals...and the spool should come right out like you said. I don't believe for a second slamming the boom caused this, if a cylinder was leaking than maybe, but not he spool.

phalynx · Mar 1, 2010

Thanks kennyD. I really do appreciate it. I ordered the parts for it. For something this easy, I'd rather fix myself than arrange to have it brought back to my dealer....

kennyd · Mar 1, 2010

Understood. But you really should at least let them know it's leaking and have them document it-just in case something else is causing it to leak...

phalynx · Mar 4, 2010

Well, after taking the whole thing apart we finally discovered what the problem was. Part #16 is threaded with an O ring in between it. It was loose. When I pulled the whole thing apart I noticed it and it made sense that the fluid was coming out of the top and not around the seal (was difficult to tell). So, we tightened the part up, put it back together, and whola!, its leak free...

If I would have only known...

Thanks KennyD!