Aloha guys, the arm cylinder on my excavator was always falling when joystick was in neutral. The other day while cleaning the arm suddenly extended all the way out and would not return. At the same time I could hear a higher pitch noise in the hydraulics and I believe it's one of the by-pass valves for that circuit. Other circuits are fine and operate as should.
I checked the cylinder today with both hoses disconnected and trying to blow air through it. It's okay; the piston holds under pressure of air and only moves a little then stops and no more air can go through.
I started the engine with the extend arm hose off and joystick in neutral. I immediately got high pressure oil shooting out of it. Just to be sure I took of the hoses of the bucket circuit and started machine and got no oil shooting out on start up. Only when I moved the joystick oil came out of the hoses.
I believe the problem is a stuck spool or valve and am about to open up that circuit but wanted to know if anyone has taken apart one with the devices or extensions of the valve body in the photos below. I don't want to open it up the wrong way and have check balls and springs fall out unexpectedly (which you should always expect). Any help would be appreciated.
I checked the cylinder today with both hoses disconnected and trying to blow air through it. It's okay; the piston holds under pressure of air and only moves a little then stops and no more air can go through.
I started the engine with the extend arm hose off and joystick in neutral. I immediately got high pressure oil shooting out of it. Just to be sure I took of the hoses of the bucket circuit and started machine and got no oil shooting out on start up. Only when I moved the joystick oil came out of the hoses.
I believe the problem is a stuck spool or valve and am about to open up that circuit but wanted to know if anyone has taken apart one with the devices or extensions of the valve body in the photos below. I don't want to open it up the wrong way and have check balls and springs fall out unexpectedly (which you should always expect). Any help would be appreciated.