Ford 3000 3pt help needed

Mathias NY

Well-known Member
I'm in the middle of spring plowing and have developed an issue with the 3pt lift on the tractor. After about 30 minutes of plowing, the lift gets slower and slower to raise out of the ground. After about 45 minutes I need to stop at the end of each pass and wait 15 seconds for it to lift. If I lower the engine rpms to an idle, it won't raise at all.

The fluid level is good and it is clear not milky. At this point its warm, but not hot and does have some bubbles in it. Flipping the lever between position and depth control had no affect. Adjusting the flow control knob also had no affect. It has no trouble holding the plow up when it gets raised.

About 400 hours ago I rebuilt the hydraulic pump and lift cover. I also changed the filters, fluid, and pressure relief valve. Since that time I have seen this problem occasionally if I max out the hydraulics, but it has never had trouble lifting the plow before.

Other than replacing the pressure relief valve again, I'm kinda short on ideas. Does anyone have any suggestions?

Thanks for looking.
 
Lift cylinder seals are likely to be getting bad and once the fluid has warmed up it thins out and leaks past the piston seals.
 
Howdy Mathias,

If you see bubbles in the fluid, the odds are that your hydraulic pump is sucking air somewhere. As the air bubbles build up in the hydraulic fluid, the lift becomes less and less responsive. I had this happen to a Kubota hydrostat one time. After it ran for a while, it became very sluggish, didn't want to go anywhere more. The hydraulic fluid was loaded with tiny air bubbles.

Possible quick fix - put some sealant externally around the suction pipe connection at the pump and at the suction pipe connection down low on the rear end/hydraulic reservoir. Look for any evidence of leakage along the suction pipe. There may be a crack in the line.

I think that the pump can also have a leaking seal that allows air entry into the system.
 
sixbales - thanks for the tip. I'll check that out.

old - The lift cylinder holds the plow up, even when the oil is hot and the tractor is idling, so I'm not convinced that the problem is coming from the cylinder or the check valve on it.

After lunch, it had cooled and I was able to try it again. This time I left the flow control valve completely open rather than closed and was able to operate for 1.5 hours instead of only 45 minutes. I'm not sure if it was the cause of the change or not.

I checked the hydraulic pressure at one of the remote ports when I started the tractor, 1900psi at idle and 2500psi at 1700rpm. An hour and a half later, the oil was hot and the pressures remained unchanged.

Since the pressure didn't change and the lift holds the plow in the air, the problem is most likely somewhere in between. If I listen closely when it struggles to lift the plow, I can actually hear what sounds like oil hitting a relief or a bypass. Lowering the quadrant lever back down will make the sound stop. Are there relief valves in the quadrant lever that can be changed?

Thanks again.
 

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