Position Control

[Dirt Mover]

I must be confused about this. My B3350 manual states " this will control the working depth of 3-point hitch mounted implement regardless of the amount of pull required". Now, I have a ballast box on mine with about 300 Lbs in it. With the position control in 5 the 3pt will "leak" down while in use. It did that at another setting too. It is not fast. It did that a couple times over a period of 5 hours in use. Do I have this all wrong? What is your experience with this?
DM

 

[85Hokie]

just about all 3 point settings are imperfect over time. In theory - position control, set it and forget it! But that still is living in a perfect world! When you lift the box off the ground and the tractor is off - does it still lower slightly, over time? In the old days - many a operator would place a piece of chain in the mix to hold the implement at the correct height. Might not have answered your question, but even despite the newness of your tractor - I would think over that amount of time, it would move a little.

 

[David Cockey]

Position control should hold the height of the implement as long as the engine is running and the hydraulic pump is pumping. There is a valve which controls fluid into the hitch lift cylinder and is linked to the position control handle and the 3 pt hitch lift levers. If the lift levers drop below the height corresponding to the position of the control handle the valve should open and add fluid to the 3pt hitch lift cylinder.

Does the position control handle stay in the same position or does it creep down? If the position control handle moves down the hitch should follow down. There is a stop below the handle in the slot the control handle moves in which can be set to keep the control handle from moving down.

 

[hodge]

Does the 3350 actually have position control? If not, then once you've let off of the handle, the 3 point is at a set level. The hydraulic system won't maintain that height, because it is no longer supplying fluid pressure, and the lift cylinder can leak down.
If it does have position control, then maybe the draft control isn't set properly.

The one thing that I HATE about my B7100 is the 3 point control- no position control. It is a shame that Kubota still builds tractors without it, and that fact would keep me from buying Kubota. Blasphemy, I know, but that one feature would be a huge deciding factor between a Kubota and another brand.

 

[HJT]

I must be one of the lucky ones with my B2650. I have left it setting in the garage for a couple weeks with the 5' blade hanging and absolutely no leak down. That blade just stayed exactly where I left it. My previous B2620 with 1/4" control would leak down in a few hours. hjt

 

[David Cockey]

B2650 and B3350 have position control but not draft control. Move the postion control handle and the 3 pt hitch follows. The 3 pt hitch lift arms always move to the same height for a given position control handle position (unless something causes it to float up).

The B7100 had simpler "up/down" control, essentially the same as what the BX series and a few other Kubotas have today. Pull up on the control, fluid flows into the hitch lift cylinder and the 3 pt hitch moves up. Push down on the control, fluid can flow out of the lift cylinder and the 3 pt hitch moves down. With the control in center position fluid does not flow in or out of the lift cylinder (unless the valve is leaky, etc).

 

[Stubbyie]

"Position" control and "draft" control are two different animals.

For a better understanding of "draft control" do a Google or other search for "Ferguson System". Ferguson brought out the first real draft control, licensed it to Ford, and then had a falling out. It's an interesting story of industrial espionage, corporate shenanigans, and contractual disputes ending in the courts.

(Just as an aside: an old Ferguson or Ford has a better draft control than virtually any modern machine.)

(Another aside: JD reacted to Ferguson by bringing out a competitive system that is considered by experts like Nebraska Tractor to be inferior in every way.)

Position control nothing more than using your 3-point to lift an implement--like a brushhog or mower or rock box or platform or whatever is hung on the 3-point.

As long as the motor is running, the setting should hold the implement. Engine goes off, implement sometimes-often-usually drifts down over time. Usually drops faster the older the machine is as seals wear.

Draft control is for soil-engaging implements like plows or disks or harrows or subsoilers. These implements are all designed--when properly secured to the 3-point lift and adjusted correctly--to "dig" into the soil. As you pull forward, the implement wants to "dig" deeper.

The true draft control exerts hydraulic pressure to lift the implement 'up' to counteract the "suck" (a technical term in the industry) of the soil.

You continue to drive forward, the implement sucks down, the 3-point lifts up---its a continuous balancing act. Have someone else drive a machine with draft control while plowing and you can watch the implement move up and down as the hydraulic system pulls up against the soil suck.

All that said, I'll bet your machine doesn't have a true draft control.

Please post back your continuing experiences so we may all learn.

 

[CountryBumkin]

Nice explanation Stubbyie.
Keep coming with those "technical terms". I love learning about tractors.

 

[David Cockey]

Dirt Mover is your tractor a B3350 or a B3350SU? The B3350 has a position control valve with a height of the hitch corresponds to the control position handle.

The B3350SU has what Kubota calls "quarter-inch" valve which works differently. With the control handle in the middle "neutral" position the hitch remains in the same location unless the cylinder or valve is leaking. Pull up on the handle and the hitch will go up until the handle is released. Push down on the handle and the hitch will go down until the handle is released.

The B3350, B3350SU and B2650 do not have draft control available.

 

[Dirt Mover]

Mine is a B3350
DM