My case 580c has limited power on the backhoe and will not do 2 operations at the same time (bucket, dipper,etc.). Checked the pressure at the loader valve (it was at spec) Replaced o-rings in outlet on loader valve, and checked the re-generation circuit in the backhoe valve. Still the same problem. Any suggestions ?
Doug, hows the power otherwise ?? I'm trying to figure out if its an engine or hydro problem..
The engine has no problems, has new injectors and pump. Runs up to rpm no problem. The loader operation has plenty of power. Its only the backhoe operation that is a problem.
If you bottom out one function ie. boom, dipper, etc does any other function try to work. Such as if you bottom out the dipper cyl. does the whole boom try to swing or boom up or bucket curl or visa versa.
Coy If you operate the dipper no other function will operate. Also when you operate the dipper it pulls the boom down (extends the cylinders). Was testing yesterday to answer you question and with the dipper bottomed out tried to bottom out the boom and when it was close to bottoming out it started jerking. Did not mention previously but hyd oil and filter in machine was just changed in machine to see if it made any difference in functions.
It sounds like the load check O-rings are probably bad. The load checks are under the circuit relief valves. Also check the power beyond o-ring at the outlet side of the loader control valve.
Coy Thanks for the input. I am putting together a test rig to check the pressure relief valves in the spools. I assume if the O-rings are bad it would show up in a pressure test ?
Let me know how it goes.
Coy I replaced all the O-rings in the valve. When I took it apart there were no O rings on the load check plugs. I installed the O rings per the part number in the parts book. When finished I tried to set the secondary relief valve pressure per the manual. None of the A or B ports would hold pressure. Any ides whats wrong ?
What pressure could you set circuit reliefs to.
The only one I could set was the boom Downforce which is only 700psi. The others would bleed of the pressure around 1800 psi as fast as I could pump. So could only get the pressure up to that.
You might want to look at your pump, pressure is resistance to flow. You need flow for circuits to work. When pumps get worn they will bypass internal. You need a flow gauge to check it.
Readjust you’re main relief pressure on loader control valve to 2350psi. When you adjust your circuit relief valves turn them back or up as needed to main relief pressure then 1/4 turn more for setting of circuit relief.