- Joined
- Feb 21, 2003
- Messages
- 26,952
- Location
- SE Michigan in the middle of nowhere
- Tractor
- Kubota M9000 HDCC3 M9000 HDC
That video is misinformation and should be removed and Mossy is 100% correct. Draft control is to be used with ground engaging implements, that is why smaller units inly have position control as the lack both the power and the weight / traction to utilize ground engaging implements such as moldboard plows or Swedish Tine cultivators to name a few.That video is incorrect.
Basically how it works:
Position control (which will be standard on almost all low powered tractors)...
There will be ONE lever next to the seat. That controls the height the 3 point lower arms will be set at and the top link bracket (where the top link adjuster is pinned to or a hydraulic cylinder is pinned to) is hard mounted to the rear casting and don't move. All control is achieved by raising and lowering the lower lift arms. There is no way to adjust the depth other than the lower arms.
Draft control is a bit more complex. There will be 2 levers next to the seat. One lever controls the lower arm height, the other controls the sensitivity of the draft mechanism. The way it works basically is, the top link is attached to the tractor with a cam shaped pin that allows the top link forging to move in relationship to the load placed on the implement. It acts against a stationary stop block mounted to the rear housing casting and has a set space between it and the moveable top link. When the ground engaging implement encounters a difficult spot, the top link will rotate slightly and contact the stop block and try to rotate further. The moveable top link will have a 'feedback rod' attached to it and the rod will actuate the 3 point hydraulics to lift the lower arms enough to lift the implement out of the ground enough to clear the hard spot. Soon as it clears it, the pressure on the top link is relaxed and the implement is allowed to drop to the preset position again.
You still use the position control lever to initially set the implement depth, the draft control lever (the second lever) only adjusts the sensitivity of the moveable top link forging when it contacts the stop block.
The 'feedback' linkage is adjustable via a threaded coupler and lock nuts and the space between the stop block and the top link forging is also adjustable by shimming or removing shims from the stop block. Kubota (because all I'm familiar with as it's all I have) recommends about 1/16" clearance between the stop block and the top link forging and that is how mine are set.
If you have say a rear mount backhoe attached, you ALWAYS want the draft sensitivity control lever set in it's lowest position or the draft control will be trying the raise the lower arms when you are digging because the upper mount on the backhoe mounts to the upper (top link mount) and will put severe pressure on the top link forging and possibly break it or the rear case. In fact, after you mount the hoe, you want the position control (other lever) in the lowest position as well.
When using the draft control, all the draft lever does is control the sensitivity of the draft control linkage, that is, how fast the draft control linkage reacts to the had spot encountered by whatever ground engaging implement you are using.
Why it's important to keep the upper link forging greased, so it can freely pivot and contact the stop block. I use mine quite a bit but when not having a mounted ground engaging implement, I ALWAYS have the draft sensitivity lever set in it's lowest (no actuation) position and just use the other lever (position control) to raise and lower the mounted implement.
I'm sure that is 'plain as mud' but of you only have one lever, you don't have draft control. You always have to have 2 levers, no matter what make the tractor is, they are all the same basically.
Just remember, when mounting a backhoe, even if it's a subframe mount, ALWAYS set the lower link link control in the LOWEST position and if you have draft control, the lever must be set in the least sensitive position.