Grading How does my three point float work GC1705?

[Leejohn]

s219 it can't be a standard double-acting valve, with that the 3pt would be locked where ever it stops and you could have down pressure.

 

[s219]

Yes, correct not standard double acting in the sense that it doesn't pressurize in both directions. It's really a double "throw" valve that pressurizes the piston for up and "bleeds to tank" for down. The cylinder for the 3-pt only takes fluid in one end (at least on the Kubotas I have looked at).

 

[Leejohn]

That is just how a SA valve works. Bty I looked at my B7800 when you posted the picture where your lever would lock down. That is just a adjustable bracket that can be moved so slow part can move it just for a little faster movement. If you move it for a little faster down it well slow it down on the up part. Its just a small stops that you can over ride and go all the way up or down and it can be moved to bind up at full up or down and hold the lever there. I cut my bracket in half so I could speed it up in both ways. Now my BX2660 doesn't have that bracket, but it seems to be a little better valve then the 7800.

 

[s219]

That is just how a SA valve works. Bty I looked at my B7800 when you posted the picture where your lever would lock down. That is just a adjustable bracket that can be moved so slow part can move it just for a little faster movement. If you move it for a little faster down it well slow it down on the up part. Its just a small stops that you can over ride and go all the way up or down and it can be moved to bind up at full up or down and hold the lever there. I cut my bracket in half so I could speed it up in both ways. Now my BX2660 doesn't have that bracket, but it seems to be a little better valve then the 7800.

On my B2920, there were adjustable sliding stops (with nuts) that you could use to set the "increment" of the quarter-incher. That would be how someone could calibrate how far the hitch moves when you bump the lever. If you slide the lever past the stops, you'd get the valves full open in either direction.

Then, on each end of the lever guide there are slots to hold the lever (have to jog the lever sideways a little). On the upper end, it will cause the 3-pt to raise all the way, and then a feedback linkage automatically bumps the lever back to center/neutral. On the lower end, it locks the lever down so that the valve bleeds back to reservoir and creates the "float".

While some have complained about the quarter-incher, I was always happy with it and thought that all these little features Kubota built into the lever/valve made it very nice to use. I like position control on my L3200, but it's not the major breakthrough some make it out to be, at least not for my uses. I almost always drop the hitch into float for using rear blade and box blade, and set height manually by eye when raising stuff. Maybe the quarter-incher on the old tractor trained me that way.

 

[JWR]

I've heard all sorts of conspiracy theories and claims that it was some Kubota scheme to nudge people to higher priced machines, etc. I don't buy into any of that. I think it is just this simple: The Quarter Incher came about to try to cater to the landscaping customer base. For what they do it was probably a great invention. The gamble was that landscaping was a big piece of the market and everyone else would just tolerate it or grow to like it or not care. As with most marketing moves, the mfr never really bares their soul as to what the reasoning was.

 

[TripleR]

I own a pre quarter-inching BX2200 and up until recently JD2305, to me at least the quarter-inching was like the lipstick on a pig, never saw any advantage over the old style and just hand bumping the controls. We recently bought a JD1025R with position control, big improvement according to everyone who uses our SCUTs, I no longer use any of them, but when I did, I sure missed position control as that's what I grew up on and have on everything else.

 

[porky69]

The 3pt hitch is a single acting cylinder which has the lift arms resting on top of the "rod end" of the cylinder, not pinned to it. The control valve applies pressure to the piston end(bottom) of the rod to lift the hitch and when you lower it the weight of the implement (and gravity) force the fluid back out of the cylinder to the tank through the rate control valve (the knob in front of the seat that controls how fast the hitch lowers).

If you hold the control in the lower position after the implement is on the ground the cylinder will continue to retract, albeit a lot slower because now there is only the weight of the cylinder rod pushing it down, this is where the "float" is. the problem is it takes longer than most people are allowing to get it to float. If you just lower the implement to the ground and release the control and drive the front tires up on a hump the implement will "float" up. To visualize this next time the lift arms are in the down position with nothing attached, lift up on the ends of the arms, they will rise up and when you let go they will drop to the original position.

I know it's clear as mud, but trust me, if you want to have float in a down direction you either have to be patient and let gravity do its thing or if you want to speed it up, open the drop rate valve all of the way and then put the control in the down position, just remember that with that valve open the implement (Plus gravity) will cause it to slam to the ground if you forget to close it down.

It is a cheap set up, hence why they use it, but it is functional. I will say I much prefer the position control on my father-in-laws Kubota B2400.

 

[atsah]

The 3pt hitch is a single acting cylinder which has the lift arms resting on top of the "rod end" of the cylinder, not pinned to it. The control valve applies pressure to the piston end(bottom) of the rod to lift the hitch and when you lower it the weight of the implement (and gravity) force the fluid back out of the cylinder to the tank through the rate control valve (the knob in front of the seat that controls how fast the hitch lowers).

If you hold the control in the lower position after the implement is on the ground the cylinder will continue to retract, albeit a lot slower because now there is only the weight of the cylinder rod pushing it down, this is where the "float" is. the problem is it takes longer than most people are allowing to get it to float. If you just lower the implement to the ground and release the control and drive the front tires up on a hump the implement will "float" up. To visualize this next time the lift arms are in the down position with nothing attached, lift up on the ends of the arms, they will rise up and when you let go they will drop to the original position.

I know it's clear as mud, but trust me, if you want to have float in a down direction you either have to be patient and let gravity do its thing or if you want to speed it up, open the drop rate valve all of the way and then put the control in the down position, just remember that with that valve open the implement (Plus gravity) will cause it to slam to the ground if you forget to close it down.

It is a cheap set up, hence why they use it, but it is functional. I will say I much prefer the position control on my father-in-laws Kubota B2400.

If you have something hooked to all three links of the hitch like a back blade etc, once the implement is on the ground you can hold the drop handle all day if you don't move the tractor the point in which the implement touched the ground is all your going to get. It's pretty simple, if you want the implement to float on uneven ground you need to hold the spring loaded handle down while in motion. I made a quick stop that fits in the slot above the handle, it works..

 

[porky69]

You don't have to hold the handle down in order to float, you just have to hold it down for a few seconds after the implement hits the ground. The 3point lift cylinder retracts a lot slower once the implement is on the ground but it will still retract as it is not pinned to the lift arms(you can make it drop faster if you play with the drop rate know in front of the seat but it is hard to get back to where you had it set). This is most easily shown with a plow or cultivator: stop forward motion of the tractor, lower the implement until it is on the ground (if you let go of the lever now and drive ahead it will stay on the surface), now before you pull ahead hold the lever in the lower position for say 15seconds (longer than is really needed but will make sure the lift cylinder is retracted, then release the handle and start driving forward and the plow will dig into the ground(without holding the handle).

 

[atsah]

You don't have to hold the handle down in order to float, you just have to hold it down for a few seconds after the implement hits the ground. The 3point lift cylinder retracts a lot slower once the implement is on the ground but it will still retract as it is not pinned to the lift arms(you can make it drop faster if you play with the drop rate know in front of the seat but it is hard to get back to where you had it set). This is most easily shown with a plow or cultivator: stop forward motion of the tractor, lower the implement until it is on the ground (if you let go of the lever now and drive ahead it will stay on the surface), now before you pull ahead hold the lever in the lower position for say 15seconds (longer than is really needed but will make sure the lift cylinder is retracted, then release the handle and start driving forward and the plow will dig into the ground(without holding the handle).

I'll give that a try, If that does work it would be great..