The 580C backhoe does not seem to have the same amount of hydraulic power as the loader. When the loader gets in a spot where it is at it's limit I can hear the engine working harder and see the exhaust thicken up a bit. The same is not true when the backhoe is at its limits- it doesn't work the engine and I can hear flow noise from the front by the loader valve area. When I let off the backhoe control lever the flow noise from the loader valve stops. I don't hear any relief or flow noise from the rear or backhoe control valve. My manual lists the 1st probable cause for "poor operation all backhoe circuits" as "Defective o-ring on power beyond fitting in loader control valve". I also remember reading about these o-rings on this forum some time ago. I've looked through my parts manual and don't see anything labeled "power beyond fitting" Are the o-rings #s 11 & 12 in the middle of this pic?
Item 10 (or 10A if yours has elbow fitting) is the power beyond fitting, if those o-rings fail the pressure that would go to the backhoe circuit simply leaks by the sleeve on the power beyond fitting and the oil returns to tank via the tank line on the loader control valve.
Yes, that long sleeve like fitting (#10?) seals off a passage inside the loader valve forcing pressurized oil out to the backhoe valve. In other words it provides "Power beyond" the loader valve, sending hydraulic power to the next valve in the line. The seal on the inside end is usually the culprit. Dang, Willie beat me, LOL!
It's all good lantraxco. :drinkup From what he's describing it does sound like a problem at that power beyond sleeve.
Thanks helping me with this! I'll replace them and post back
Ok, I have replaced the O rings. I had to rebuild the battery box. When I opened the battery compartment to access the Power Beyond fitting, the bottom hinge broke off and I almost ended up with a couple of batteries on me feet! Anyway, it still does the same thing. I ran it a while today and after it was good and warmed up, it was better. Once warmed up, it seemed to have more power and I could hear the individual reliefs opening at the rear under the backhoe lever when at limits and no noise from the front. When I first started out and after lunch break, the relief/flow noise was from the front loader control valve while using the backhoe. This is at its limit- not necessarily at the mechanical stops, sometimes when hitting a root or taking a big bite and movement stops the flow noise starts from the front. I think if taking too big of a bite, the individual reliefs at the backhoe should open, not something in the loader valve right? I don’t like the Power Beyond Fitting- it is the 90 deg angle style. It has straight threads with a jamb nut. With the jamb nut backed all the way off, the fitting bottoms out in the loader valve almost but not quite where it has to be to line up with the pipe. The fitting has to be backed out of the loader valve ¾ turn and then secured with the jamb nut to line up with the pipe. The machined area for the inner o ring in the loader valve is not very deep. I’ll have to take some measurements to see if it’s going in deep enough for a good seal. Maybe I’m chasing something that is not a problem. It does seem to have more power when the relief noise if from the rear than when it comes from the front. To put it on the boom lock when the relief noise if from the front, the rear end has to be jacked high and get a good running start raising the boom. With no noise from the front, the thing practically puts itself on the lock with little effort. I’m working in a blueberry field right now so it’s easy digging.. When I’m done I’ll have to get a pressure gauge to see what is available to the backhoe Any Ideas? Thanks
Speaking generically the main relief will open before the port reliefs in the backhoe valve, they're only there for situations where say you have enough leverage while curling the bucket to cause the stick or boom to move even though the control valve spools are centered. Swing would be a probably exception as usually they're set up for a lower pressure than the main relief, depends on the design. Sounds like you fixed a problem with the power beyond seals, but have you put a gauge on the system to see what you've got? The main system relief in the loader valve should be adjustable and may need to be reset due to age, wear, heat. Also some of the port reliefs in the backhoe valve stack may also be opening at a lower pressure then specified. These may be adjustable, shimmable, or need replaced.
I bought a pressure gauge off of EBay for $9.95. I don’t have a suitable hose to connect it, but removing the plastic trim piece from around the loader valve gave room to thread the gauge directly into the test port. All seems good now. There was this chattering screeching noise when at the limits when using the backhoe, but not anymore. I uploaded a video to U Tube if any of the experts on here would watch and listen to it to notice anything I’m missing that would be great. It’s hard to video everything at the same time. I’m running through all the controls one at a time and am getting the same pressures for loader curl and all the individual backhoe controls. https://www.youtube.com/watch?v=FV79sZfOnrc The backhoe is loading the engine now after replacing the o rings. I think I’m good now. Thanks for the help.
IT don't get any better than that. Have fun!
No argument here. :drinkup