Hi, I am new to this forum. We have a John Deere 410 Backhoe, s/n 342132T. The hydraulics for the backhoe suddenly got very slow and the loader stopped working at all.The first thing I did was check the output pressure of the pump. It was only about 800 PSI.
Next I removed the spring in the pressure control valve that prioritizes steering over the loader hydraulics effective bypassing this function so I could raise the loader even if I couldn't use it for any lifting or work. This worked and I can now raise the loader, albeit extremely slowly with no working power. I did this so I can move the machine around (the loader was on the ground).
Next thing I did was to try adjusting the output pressure with the adjusting screw on the port on the bottom of the destroke control valve on the hydraulic pump. Turning this screw either way made no difference in the output pressure (still about 800 PSI)
The next thing I did was to pull out the cylindrical pre-filter screen that is about 1.5 inches in diameter and 8 to 10 inches long that is inside the fluid reservoir where a short rubber hose connects the reservoir to the hydraulic filter assembly. The screen was not damaged and it was clean. I reassembled it.
The next thing I did was the unscrew the cap on the 2nd port on the destroke control valve that is next to the pressure adjustment port. My manual shows a screen inside this port that I wanted to check. When I removed the cap there were a significant amount of metallic shavings in the cap and in the port. Obviously the pump is bad but what I don't know is how to determine whether the metal shavings came from inside the pump or somewhere else in the hydraulic system and whether they have spread into other parts of the system.
When I was checking the pre-filter screen in reservoir there were none of these metal shavings in the screen and there were none in the hydraulic fluid filter (I had to remove it too, to get the screen out). I removed the cap on the pressure adjusting port on the pump and removed the innards from this port. It was clean with no metal shavings, but the parts inside this port are different from what is shown in my parts manual. I know the pump was replace about 17 years ago. Maybe it is a different pump from the original that is functionally compatible?
The parts inside the port where the metal shavings are do not match the manual either. There is no screen in this port as the manual indicates.
How do I determine where the metal shavings originated from? And what should I do to insure that when I install a new pump, it does not get damaged?
The uploaded file is photo of the metal shavings along with the cap for the port. This is approximate 1/3 to 1/2 the amount of shavings that were in the port and as you can see it looks like there is damage to the inside of the port cap. As I mentioned above I found no trace of these shavings in any of the other places mentioned except this port.