I'm having issues with low hydraulic power on my backhoe. It started when I was using a mulcher that I bought. It's on the boom side and I had to run a case drain line, with a filter for it. i know it uses a lot of hydraulic flow and wasn't surprised that the other controls were sluggish when it is running, but when I'd stop the flow to the mulcher, the other controls would return to normal. Then i started noticing that the hydraulics were weak and sluggish even when the mulcher wasn't running. It was now so bad that to lift the front bucket, I had to step on the throttle. So, my first action was to change the fluid and filter. This made no difference. Since the problem was affecting all the hydraulics, I concluded that it must be the pump. So, i ordered a new one and replaced it. i thought that had fixed it as it was working at first, but after a short time, i started noticing the sluggishness coming back. i think there is something going on that caused the original pump to fail and I'm afraid that I'm probably damaging the new one. I took off the mulcher and put my 12" bucket on and that didn't make any difference. Like i said, everything is sluggish, but the most noticeable symptom is, say I'm raising the boom: if i pull back gently on the stick, it comes up very slowly, but if i pull the stick all the way back, I feel a surge and then a release, as if the fluid is being diverted and the stick goes dead. I have the service manual and it has a section for diagnosing hydraulic problems, but it requires flow and pressure gauges I don't have and my service guy is backed up about 4 months. The pressure gauges wouldn't be that expensive, but I haven't been able to find a flow testing kit that I can afford. My other thought was maybe there was air in the system, but the manual says you don't need to bleed it and has you heat uo the fluid and then work the controls and says that should remove all the air. Any thoughts? anyone know of a flow tester that the average guy can afford?
I would imagine the mulcher gets the hydraulic oil very hot from running constantly. Maybe the heat damaged some seals in the valve bodies?
that makes sense. I've ordered a flow tester from China. So, hopefully that will help me to determine. i don't see a temperature sensor for the hydraulic fluid, which surprises me as it has sensors for everything. That leads me to another thought: If the cooler can't keep the oil cool, would overfilling the oil reservoir help to keep the fluid cooler? Would it hurt anything? I know you would have to leave room in the tank for expansion, but i bet you could get a couple of extra gallons in the reservoir.
I don't think you could add enough oil to lower temps. It would expand and start leaking from the reservoir or over pressurize the reservoir. This could cause the suction line (or other lower pressure lines) to burst or create other leaks. There needs to be room for expansion in the reservoir. Maybe an aux. cooler could be added with an electric fan? Mulchers need large reservoirs and lots of cooling.
Not sure I've ever heard of someone trying to run a mulcher on a backhoe before. You are doing something a backhoe was never meant to do and it sounds like it might have come back to bite you. As WD mentioned I'm guessing you way overcooked the hydraulic oil, which could lead to many possible failure points. First thing I would do is sell the mulcher or find a machine better suited to run it. Next, I think you are on the right track testing pressures/flows. Could be seals anywhere in the system bypassing oil (valve body(s), relief valves, pump, etc etc).
Your probably right although it's a pretty small mulcher. Folks run much bigger mulchers on a skid steer which doesn't have near the amount of fluid capacity.
The hydraulic oil routing in a skid steer is no comparison to your 580N. Most of them are designed to run mulchers and hydraulic hammers. Your 580N hydraulic oil goes from the pump to the loader valve and then the backhoe control valve. I would think that the hydraulic oil filter in a 580N would be restriction in a high flow situation that a mulcher requires. And that would polly cause the oil temp. to rise. IMHO of course.
So, once i figure out what the problem is and fix it, i should probably add something like this: https://www.loftness.com/product/cool-flow/
Something like that would certainly help but I imagine is quite pricey.
yes it is, but so is fixing the backhoe. maybe i'll look into fabricating one.
Might be difficult to fabricate an effective cooler.