3pt hitch issue

crazyal · May 2, 2014

My neighbor has an older 4wd Yanmar tractor (I forgot to get the model number) with what looks like a 3 cylinder diesel (maybe 30ish HP?). It has 3 forward gears and a reverse lever mounted next to the steering wheel with the clutch on the left and both brakes on the right. Last week it started pushing oil out of the breather tube. Turns out that the seal on the hydraulic pump went and was pushing hydraulic oil into the engine. He has it repaired but now has an issue with the 3pt hitch. It only works when you raise or lower the loader. If the loader is disconnected the 3pt hitch does nothing, when the loader's lines are connected it's slow it starts and stops randomly. I did notice that it has draft control. We're wondering if there's part of the seal that made it's way into the 3p valve. Or possibly there's another issue with the 3pt valve. I can get more information this weekend

Gjamtrac · May 2, 2014

Sounds like he never re-filled the tranny after pushing all or most of the oil out of it.

winston1 · May 2, 2014

I am "guessing" he unhooked the loader while repairing the leak?? I would also "guess" the output of the pump goes through the loader valve before reaching the 3 point.
Does the loader work as always??

"If the loader is disconnected the 3pt hitch does nothing" The 3 point would also be disconnected unless you tied the in and out lines together.

pmsmechanic · May 2, 2014

I'm wondering if the loader hydraulic lines have a male and female end and that they should be coupled together while the loader is off the tractor. Could also be why the seal went on the hydraulic pump as the oil has no place to go.

crazyal · May 3, 2014

The hydraulic fluid was topped off after the pump was repaired. There's a hard line that goes from the pump to the hydraulic manifold under the seat where the over pressure valve is located and the knob to adjust the 3pt hitch. Rubber hydraulic lines run from that to the loader valve. The manual shows plugs in the manifold that get removed if adding a loader. The tractor does have one remote (it's not being used). One of the remote lines connects to the PB port on the manifold while the other connects to the loader valve. My guess is that the manifold only has one port for hydraulic fluid to return to the tank and the loader valve is connected to it so the remote line connects to the loader valve.

I need to get a new pressure gauge so I can check the pressures. He's in no hurry as all he uses the 3pt for is skidding logs. I guess it's possible one of the loader spool valves is broken and when it's in the neutral position it's allowing hydraulic fluid to flow back into the tank unrestricted. If so I should see it when checking the pressure. On the side of the loader valves is what looks like a pressure relief valve. The manual doesn't include any information on the loader as it looks like it was added later.

winston1 · May 4, 2014

I am really a bit confused but thinking when the loader was unhooked the two lines should have been connected. If not, the fluid had no place to go. Probably caused a relief valve to go off.

Still no knowledge of model number?

shovelrider · May 4, 2014

I agree model number, and pics would help with poss. identifiying the problem.

crazyal · May 10, 2014

I'll try to get some later this week. He's using it as is in the woods, too muddy to walk in and get pictures. The best I can describe it is the steel hose coming out of the hydraulic pump goes to a manifold under the seat. The loader valve is mounted on the right side of the steering wheel and is connected to the manifold with rubber hoses. It doesn't look like a factory install. The tractor most likely was sold without a loader. Since he's not worried about fixing it I'm not going to push it but I really would love to know what's going on.