Hydraulic question on a Kubota M 6800

[HCJtractor]

I hooked up my new grain drill to the 3 point hitch and lifted it. Weighing in at 3000 lbs, it was a load. I also tilted it forward with the hydraulic top link to gain more ground clearance. I then tried my FEL and it would barely move, very slow response. When I sat the drill down, the FEL seemed to be normal. I suppose the hydraulic system was overloaded. Is this a normal response? I was lifting it to load onto my trailer, and as I go up the ramps, it would be nice to be able to alter the FEL just to get clearance and balance. Just wondered if this is to be expected or if something is not as it should be. Never had that happen before. If I have a bush hog or disc on the rear, the FEL always works fine. Of course, the drill is somewhat heavier.

 

[J_J]

The 3pt should be in neutral when using the FEL, or it will cause problems with back pressure.

 

[HCJtractor]

Thanks JJ. By neutral, I assume you mean with no load at all, with the drill resting on the ground? Frequently, I drive around with my disk, box blade, or cutter raised with the 3 point, and the FEL works just fine. Is the difference simply the excessive weight of the drill that is causing the FEL to almost not work when the drill is lifted? I am o.k. with that if that is the case, but just wanted to make sure this response is normal, not an indication of some issue in the system.

 

[Leejohn]

I would say you are right at the point of maxing out your 3pt and when you use the loader it opens the relief valve, then loader well work slow or not at all.

 

[J_J]

By neutral, I mean you have the load whee you want it, and then you go to neutral. This locks the 3pt in place and no fluid gets in or out.

With the 3pt in neutral, the fluid from the pump flows through the 3pt valve with no resistance.

Also when using the FEL, it is first in the series flow path and it has priority, and there is usually no fluid available for the 3pt, unless you are in the feather mode. Then the fluid is shared by the FEL and the 3pt, assuming the 3pt is not fully loaded.

Try not to use both at the same time.

 

[Willl]

neutral

Neutral ?

Must be a Kubota thing.

 

[J_J]

What position are you in on the 3pt if you are not raising or lowering? That means that the 3pt cyl is getting no more fluid and not dumping fluid.

If your piston or the 3pt valve is not leaking, the load will stay where it is in neutral.

Excerpt:

The position of the control valve determines where the oil goes next. If the control valve is in neutral, the oil is simply directed back into the reservoir (transmission housing). If raise is selected, the oil from the pump is directed, by the control valve, into the lift cylinder, causing the lift arms to rise. If lower is selected, the oil from the pump is directed, by the control valve, to the reservoir (just like neutral); however, a passage is also opened which will allow oil to escape from the lift cylinder, allowing gravity to lower the lift arms.

 

[Egon]

3-Point Hitch:
Rear Type: I,II
Rear lift: 4550 lbs [2063 kg]

Above information for the Kubota M6800. So put that 3000 pounds back a little farther and chances are you are at the three point limit as per Leejohn.

 

[HCJtractor]

I had my drill raised to the max with my 3 point. I then tried to raise and lower the FEL. I was going up my trailer ramp. Wanted drill high for clearance and had to raise FEL to clear ramps, but then needed to lower FEL as i went up to keep center of gravity low. Thats when it was slow to respond.

Still confused on "neutral". How do you put 3 point in neutral if it is raised to max? If it is not either going up or down, is it not in neutral? If i was not moving the drill with the 3 point, why was it using hydraulics if the valve was closed? Sorry but i am a hydraulic simpleton.

 

[Willl]

Still confused on "neutral". How do you put 3 point in neutral if it is raised to max? If it is not either going up or down, is it not in neutral? If i was not moving the drill with the 3 point, why was it using hydraulics if the valve was closed? Sorry but i am a hydraulic simpleton.

I'm confused as to what the heck JJ's talking about also.

 

[foreman Etexas]

I'm confused as to what the heck JJ's talking about also.

Seems like hes saying that if the 3point is still trying to lift load or trying to keep it in the up position,that your not also able to pump the needed fluid to the loader at same time. Does your 3point leak down when you park the tractor with load or will it hold it up,(say several hrs)?

 

[Willl]

Of course it leaks down when off, they all do.

But when running, linkages connected to hydraulic valves lift the 3pt to the point where it matches your lever/handle. Once matched, it automatically goes to "neutral".

At least all the ones I played with.

Are Kubota's different ?

 

[J_J]

What is it that you don't understand about the neutral position. Did you not read the data that I posted?

There are a lot of people that don't know that on some tractors, that with the 3pt lever in the raise position, that you may be causing the relief to activate, and that puts the 3pt relief pressure back through the hyd system.

Neutral position for the 3pt is where the lift arms are not going up or down. Maybe some of you call it something else, but that is what it is, neutral, meaning not doing any work.

Not moving up or down = neutral valve position

Put a hyd gage at the 3pt and see what the pressure is when the 3pt is in the fully raised position. Some 3pt valves will return to neutral automatically.

 

[Willl]

that with the 3pt lever in the raise position, that you may be causing the relief to activate, and that puts the 3pt relief pressure back through the hyd system.

Then their linkages are are out of adjustment and it would do the same without any load at all.

 

[Willl]

Did you not read the data that I posted?

What data ?

 

[J_J]

Seems like hes saying that if the 3point is still trying to lift load or trying to keep it in the up position,that your not also able to pump the needed fluid to the loader at same time. Does your 3point leak down when you park the tractor with load or will it hold it up,(say several hrs)?

In theory, with a perfect hyd 3pt system, it should hold up the attachment until you lower the unit.

Some 3pt levers will auto return to neutral, but they all have a neutral position.

 

[J_J]

What data ?

Post #7

 

[Willl]

Post #7

This was a quote from somewhere ?

Got a link ?

 

[foreman Etexas]

Of course it leaks down when off, they all do.

But when running, linkages connected to hydraulic valves lift the 3pt to the point where it matches your lever/handle. Once matched, it automatically goes to "neutral".

At least all the ones I played with.

Are Kubota's different ?

I can leave mine in shed all nite,with something on 3pt in the up position and it will still be up in the morning when I go back,or for days...............
Kubotas must be different!!!

 

[Willl]

but they all have a neutral position.

Not something that's selectable by the user.

Like I said, most all 3pts find there own neutral when it satisfies the lever location.