Trouble diagnosing hydraulic issue

[patricksievert]

I've got a 61 Farmall 560 gas that I'm having hydraulic trouble with. I get a pulsating whine when the hydraulics are not engaged. if I engage the three-point hitch or any of the bucket hydraulics, the whine largely goes away. Engaging the PTO does not make the whine go away. in addition to the whine, the hydraulics are slightly jerky when lifting. Nice and smooth and lowering. Power seems to be reduced about 25% based on lifting capacity.

I changed out the fluid back in the fall, and replaced the filter. I checked that and the filter is clean. I pulled the screen on the pressure relief valve, and the screen was collapsed, but not clogged. Got the screen opened back up, still having the same issue.

I have not yet tried changing the pump, because the pump was new right before I bought the tractor a year and a half ago and it has minimal hours on it.

Hoping somebody can point me in the right direction

 

[Janicholson]

I've got a 61 Farmall 560 gas that I'm having hydraulic trouble with. I get a pulsating whine when the hydraulics are not engaged. if I engage the three-point hitch or any of the bucket hydraulics, the whine largely goes away. Engaging the PTO does not make the whine go away. in addition to the whine, the hydraulics are slightly jerky when lifting. Nice and smooth and lowering. Power seems to be reduced about 25% based on lifting capacity.

I changed out the fluid back in the fall, and replaced the filter. I checked that and the filter is clean. I pulled the screen on the pressure relief valve, and the screen was collapsed, but not clogged. Got the screen opened back up, still having the same issue.

I have not yet tried changing the pump, because the pump was new right before I bought the tractor a year and a half ago and it has minimal hours on it.

Hoping somebody can point me in the right direction

The screen attaches to a valve body with an orifice. this small hole determines when the system bypasses to the reservoir, or pressurizes up to deliver hydro to valving and end use cylinders/motors etc. The orifice is too small and causes cycling of the system pressure (against blocked valves. I think IIRC that the hole can be drilled out to 1mm (.0394") This increases the flow through the valve orifice but allows the system to still regulate flow. Jim

 

[rustred]

have you made sure the oil level is full by removing plug on the left side. jerky movement is usually low oil from my experience or plugged oil filters. have u replaced the hyd. oil filters.???

 

[rustred]

another thing... plug in a hyd. gauge into the hyd. outlets and check you pressure when u operate the lever. do that and report back. till a person knows the pressure output its shooting in the dark.

 

[patricksievert]

OK I was finally able to get a pressure gauge on it. I'm reading about 1250 psi, but with every whine pulsatin the pressure drops to somewhere between 500 and 1000 psi.

One of the couplers going to the bucket controls was leaking slightly so I replaced that in case air was getting in there. Fluid level is good. I'm still getting the same issue.

 

[Janicholson]

OK I was finally able to get a pressure gauge on it. I'm reading about 1250 psi, but with every whine pulsatin the pressure drops to somewhere between 500 and 1000 psi.

One of the couplers going to the bucket controls was leaking slightly so I replaced that in case air was getting in there. Fluid level is good. I'm still getting the same issue.

Did you do what I suggested! There may be no other solution. Jim

 

[Fritz Maurer]

If you would classify your description of the gauge action as ‘erratic’, it sounds like it is sucking air somewhere between the pump and the reservoir.

 

[used red MN]

The screen attaches to a valve body with an orifice. this small hole determines when the system bypasses to the reservoir, or pressurizes up to deliver hydro to valving and end use cylinders/motors etc. The orifice is too small and causes cycling of the system pressure (against blocked valves. I think IIRC that the hole can be drilled out to 1mm (.0394") This increases the flow through the valve orifice but allows the system to still regulate flow. Jim

Jim left out a lot of information. I would have directed you to your old post from October but it seems that the last CNHI update may have made old links not work.
In the link in the Hydraulics section look at key
13 in subsection 225. In there is likely the problem valve. Then look at subsection 237 it gives you the breakdown, even though it calls it a plug I think part 10 is where the problem orifice Jim is explaining lies. Hopefully he will correct me if I am wrong. CNHI Farmall 560 parts catalog

 

[rustred]

ok ,... u said the pump was changed out. better check the pump suction to be sure the o ring is installed on the suction. sure sounds like u have a suction leak to me. there is also 12 and a 17 gpm. pumps and also check the trans. oil for milky bubbly looking,... means u are sucking air. the hyd. starts at the suction so thats the first place to start looking. more so that you say the pump was changed, as many problems are man caused.