Grading How does my three point float work GC1705?

[s219]

Then why wouldn't you set it at the depressed level and then it will float up and down to the other levels? Why would you need to keep holding it down ?

That may not work depending on how the hydraulics are setup. You can test this when there's nothing on the lift arms. With the lever centered, go lift the arms up and see if the 3-pt stays at that raised position or goes back down to where it was. Without a true float position and/or position control, the hitch will most likely not drop back down.

That may be why he said he had to hold the lever down before -- that would have created a float. As I understand the problem description, when the front of the tractor hit a bump, the blade was being pressed up at the rear, and not returning back down.

Remember, with no downforce and no position control, these basic 3-pt hitches are pretty limited in what they can do.

 

[atsah]

That may not work depending on how the hydraulics are setup. You can test this when there's nothing on the lift arms. With the lever centered, go lift the arms up and see if the 3-pt stays at that raised position or goes back down to where it was. Without a true float position and/or position control, the hitch will most likely not drop back down.

That may be why he said he had to hold the lever down before -- that would have created a float. As I understand the problem description, when the front of the tractor hit a bump, the blade was being pressed up at the rear, and not returning back down.

Remember, with no downforce and no position control, these basic 3-pt hitches are pretty limited in what they can do.

Thanks for all the input guys.. I think I know what I need to do while using my back blade.. I messed with it yesterday, if I just drop the blade in a low spot, the hitch will go up and down to that point..

 

[jeepcj7]

ATSAH - you are absolutely correct in your observation. There is no true float position on the GC 3 point. Put if you do as you suggest you will get free floating up an down movement. To get float would require upgrading to a model 1526 tractor.

 

[atsah]

ATSAH - you are absolutely correct in your observation. There is no true float position on the GC 3 point. Put if you do as you suggest you will get free floating up an down movement. To get float would require upgrading to a model 1526 tractor.

Ya it takes a little getting use to but it does work..

 

[JWR]

"It has a 1/4 incher valve, which means you have no set positions at all, just the ability to move the 3-pt up and down between the lower and upper limits. There is no feedback mechanism to maintain a fixed/repeatable level like you have with position control."

S219 -- Educate me -- I never heard of a 1/4 incher. If one can move the implement up or down by 1/4" increments but no "position control" then it is a float-only system ? There is no downward force on the 3pt lift arms I'm sure. Then how does one ever hold an implement up ?

Meanwhile found an old 2011 post (which by the way you were in on!) that offers a YouTube explanatory video. This is a very good tutorial at
YouTube - ‪kubota B7610 Quarter Inch Valve versus Position Control‬‏

My impression is that the quarter incher was a handy thing for some users who did a lot of landscape work where a "position tweaker" was handy compared to a "position control" that the whole world understands. Now that I see what it was, I say it belongs the same place as 8 track tapes and Betamax VCRs.

 

[AxleHub]

I'm going to use an example as numerous posters seem to have a misunderstanding in my opinion of terms relating to:

float vs 3ph control

1st a statement . . . its my understanding that all modern 3 point hitches oerate with float . . .a 3 ph in any form only determines the bottom setting by control valve. (Raising or lowering the 3ph is determining the BOTTOM setting).

The setting of the bottom setting is done by your 3ph control valve and you can have 1 of 3 types:

Choice 1. Old style was up and down . . think of it as a manual seat adjuster on a car

Choice 2. 1/4 inching allows the setting of 3ph bottom postion like #1 but also fine 3 point adjustment. Think of it like having electric seat adjustment in a car.



Choice 3. Position control allows the setting of 3ph bottom postion like #1 but also a repeatable 3 point adjustment. Think of it like having MEMORY electric seat adjustment in a car.


All 3 of these set the bottom that grabity can force the 3ph to drop to. Unlike a front end loader . . a 3ph has no downward power of its own unless you have a hydraulic controlled top link which is still heavily dependent on gravity. The concept of float is not related to the 3ph control valve. The control valve sets the bottom the implement can travel . . But it does not force or push that implement to that bottom . . Thats what gravity does (and land contour).

 

[Leejohn]

The 1/4" 3pt is only a SA hyd control valve so that you can move the 3pt real slow up and down.

 

[JWR]

The 1/4" 3pt is only a SA hyd control valve so that you can move the 3pt real slow up and down.

Surge anticipation ?

 

[TripleR]

Been lots of discussions on this over the years, Chuck passed away some time ago, this may be worth reading, it took me a while to figure out and still hate it.: http://www.tractorbynet.com/forums/...212121-quarter-inching.html?highlight=quarter

http://www.tractorbynet.com/forums/...-quarter-inching-valve.html?highlight=quarter

 

[s219]

The simplest way I can describe it is to think of a standard double-acting, spring-return-to-center hydraulic valve hooked up to a hydraulic cylinder. Hold the valve one way and the cylinder extends, hold it the other way and it retracts. If you were to "bump" the valve in either direction and let it return to center, the cylinder would briefly move in or out. If somebody specially calibrated the return spring for a certain rate, then they could roughly control the increment by which the cylinder moves its way in or out when you bump the lever.

That's exactly how the quarter-incher works -- it's a standard double-acting, spring-return-to-center hydraulic valve, but the springs have been chosen so that each bump of the lever between the "inching" stops moves the 3-pt hitch about 1/4 of an inch. If you hold the lever all the way in either direction it behaves normally and the hitch keeps moving. It's only when bumping the lever that you get the 1/4 inch increments.

The downside to the quarter-incher is that there is no correlation between lever and vertical position of the 3-pt hitch. You can move the 3-pt up or down, but you have to eyeball the height yourself. This is in contrast to position control, where you basically set the height directly using the scale on the lever, and it's repeatable every time. The other big difference is that the quarter-incher can drift down over time, and you'll periodically need to raise it manually. Position control has a feedback loop and will automatically adjust to maintain vertical position. If you have position control, you may have occasionally seen the hitch bump up as the feedback loop does its thing.

All 3-pts will float under the influence of gravity, at least until the lift arms reach their lower limit. To get float with position control, just push the lever to the lowest setting. To get it with a Kubota quarter-incher valve, you push the lever all the way down, past the lower stop and go into detent (the lever will stay there). With the Massey discussed here, it doesn't seem to have a true float position, so you either need to hold the lever down, or find a low spot and drop your implement all the way down there, so that you've found the lower limit of the 3-pt arms.