Archive for Compact Tractors

Tractor 3pt Hitch Draft Control Types

First we must determine the meaning of the word draft.

Draft = Depth

Draft = Pulling force

For the purpose of this article it is important to note that a tractors draft control is NOT a depth control system. It is a LOAD control system controlling the load placed on the tractor by an implement and it is set by the operator by the movement of the 3pt hitch hydraulic rockshaft control valve or thru mechanical or electrical movement of the rockshaft valve. Now we can see that this lever also controls/limits the depth an implement may go into the ground but this control of depth is affecting the vertical load placed on the rear of the tractor. As the depth of an implement increases so does the draft (pulling/vertical load) increase until horsepower or traction has reached its limit and the tractor stalls or spins.

For our John Deere tractors they use three types of draft control systems:

Select Control Type: This is the most basic system that John Deere uses to control the 3pt hitch system. This type uses a rockshaft control lever that has an up, down and neutral position.  Implement positioning is controlled by how quickly an operator can return the lever to the neutral position. You push the rockshaft control lever forward to lower and back to raise an implement. The middle position is neutral and on newer tractors the control lever will return to neutral automatically as soon as the operator releases the control lever from up or down positions while some older tractors the operator had to return the lever to neutral manually. With this basic system an operator may get the implement in the same position 1 out of 100 times. This type is neither precise nor accurate.

Position Control Type: This type of control system involves a rockshaft control lever that has a full up and full down position as well as the ability of stopping at any point in-between. This JD type usually uses a scaled strip next to the control lever with a moveable stop so an operator may raise and lower the implement to the predetermined “stop” position. If you were looking to have your plow, box blade or mid-mount mower raise and lower by the 3pt hitch to the same position this would be the control type you would want to select. It should be mentioned that the precision and accuracy of the position control is not mentioned and this is due to lack of data but the precision appears to be relatively high.

Load Sensing Control Type: Load-sensing types are normally used in conjunction with the position control type and uses mechanical or electrical sensors to control the positioning of the 3pt arms as load forces increase or decrease. Load-sensing is found on John Deere tractors that are capable of larger ground engaging equipment, as the load-sensing was originally designed for plowing implements. When used with position control the load sensing controls will raise the 3pt arms when the draft increases and lowers them back to the position control set stop point when the load decreases.

Some historical types of load sensing used the top link of the 3pt hitch as the control point. The top link had a coil/leaf/torsion spring that would attach mechanically to the rockshaft control valve and allow for raising or lowering of the 3pt arms based on the load conditions placed on the top link. This mechanical-hydraulic system was very popular. Another variation of this same system mechanically attached to the lower arms verses the top link. This change was more prevalent when farmers were switching from single plows to multi-furrow plow setups. Still there were other older systems that monitored rear axle torque to raise and lower the 3pt arms and ones that used a separate wheel system attached mechanically to the rockshaft control valve to control the 3pt arms.

Newer load-sense control types use electro-hydraulic systems to control the movement of the 3pt arms. One type of the electro-mechanical systems uses electrical sensors the are inside the rockshaft cover or outside and connected to a mechanical lever that attaches to the lower 3pt arms and the control of the rockshaft control valve can be mechanically controlled or with electronic solenoids. Another electrical system uses all electronics to monitor the load on the tractor and move the 3pt arms. It does this with electrical sensors on the 3pt arms or rockshaft and sensors that monitor the speed of the tractor (with the aid of radar, GPS, or axle speed sensors) and either sensor input can cause the movement of the 3pt arms. The electronic systems are all controlled with the aid of an ECU that can monitor all the inputs and control the 3pt arms with no operator input once the system is set and activated.

 

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What is “Regen” or the “Regenerative” function of a FEL Valve? Read it here…

Regen is a “feature” of most modern FEL (Front End Loader) valves, it’s on the Dump (joystick far right) circuit, and is also referred to as “Fast Dump”. The reason it is nice to have is that without it, the weight of a filled bucket can actually “pull” the bucket down faster than the fluid can enter the other side of the cylinder, this will create a air pocket and give the bucket a “floppy” feeling until the joystick is held in the dump mode a few seconds to refill the cylinder pushing the air past the seals. So we add “regen” or “regenerative” function to the valve.

Regen solves this problem by actually filling both sides of the cylinder at the same time with hydraulic fluid. But how will that work you might ask? Well, because there is more volume on the side of the cylinder that extends it since the rod is taking up space in the other side, it “overpowers” the rod side and lets the cylinder extend-thereby dumping the bucket. So since now both sides of the cylinder are “pressurized”, the air pocket cannot develop, eliminating the “floppy” bucket syndrome. One other added bonus is that the bucket actually dumps faster due to the higher flow rate required to do all this, that’s why it’s referred to as “fast dump” sometimes.

So, now you may be asking “This is cool and all that, but why do I need to know about it?” The answer to that is simple, if you ever try to run a snow plow with two SA (single acting) cylinders, or a cylinder that drives a chute rotator on a snowblower you will soon find out that they won’t work if you push the joystick to far right into the regen mode. The plow won’t work because since both lines are pressurized-both cylinders will be trying to extend at the same time binding everything up. The rotator won’t work because there is no weight pushing the cylinder closed like there is on the loader.

On most, if not all John Deere tractors there is a “lockout” the limits how far the joystick travels to the right to keep it out of the regen mode.

John Deere 1026RI took delivery on mine yesterday and had a chance to mow with it and spend 3 hrs or so working with the FEL and Backhoe. This brief description is in comparison to mowing with an X724, which I will probably sell.

Comparing and contrasting the X724 and 1026R is like comparing a small nimble SUV or Jeep to a large SUV. I can’t help but draw this conclusion when contrasting them.
A Toyota analogy: When I had my 4Runner for a few years, we decided that we might want to upgrade to a Sequoia. The 4Runner is very nimble, quick-handing, but somewhat small. We test drove the Sequoia and WOW what a difference! The larger SUV was like a lumbering behemoth in comparison. Turns were slower and took more effort. Stopping wasn’t nearly as quick. Body roll was pronounced and the front dipped a lot during heavy braking. It took a good bit longer to stop. The ride was a lot rougher. However, it felt much more solid. We didn’t really like the Sequoia at all. It lost many of the qualities we liked about the 4Runner.

Now that I’ve had a few hours on the 1026R, I can draw a similar comparison to the X724 for grass cutting. Let me just start out by saying that if you just want to cut grass, BY ALL MEANS get the X700 series with AWS (preferably diesel with the deluxe seat) and forget the 1-series – especially if you have obstacles or any slopes. The X700 series with AWS are a grass cutter’s dream. They are quick, incredibly nimble, stable, with a low center of gravity, and zip through the thickest zoyzia grass, bagging or not. Cutting my grass on my X724 is actually a lot of fun because my grass area is fairly small with lots of obstacles. When I’m done, I feel like I just ran a road course – and the yard looks great.

Compared to the 1026R – what a difference! Not that the 1-series is bad, it’s obviously a tractor first which can “also cut grass” because it has a MMM attached. I’d never call it a “lawn mower” or “garden tractor.” It’s significantly heavier. Although the 1-series can turn really sharply, they’re harder to turn because steering effort is higher and they require more wheel turns. You must take care not to turn to quickly or you’ll scuff the grass (yes, with turf tires). The lack of AWS makes a big difference when cutting in and around obstacles. The firm ride quality isn’t nearly as good, but the deluxe seat certainly helps. I’m sure part of it is a learning process for me because I’m used to the AWS, but I have to think a bit more when going around obstacles on the 1026R. When/if I sell the X724, it will take me a good bit longer to cut with the 1026R than the X724 because of the weight and lack of AWS. Quick sudden turns at decent speed are no problem for the X724, but not so good on the 1026R. This next thing may be a setup issue with mine: when I cut grass in high range, if I quickly release the forward pedal (even at slow speed), it acts like I hit reverse, so the reverse detector kicks in and shuts off the PTO and engine, then scrolls a message across the dash to the effect of “engage LO” or something (I’ll clarify next time I see it). Going to get that checked. In low range, this doesn’t happen. Low isn’t quite fast enough for efficient grass cutting.

On the other hand, if you have lots of open areas to cut with little or no obstacles, the 1-series might be your ticket. If you need the attachment capability, it certainly is better. I’m not dissing on the 1-series. Sitting side-by-side, the look fairly similar in size. The 1 sits a bit taller – especially the seat. But it’s kinda hard to find an X700 series tractor loader backhoe, so I’ll keep the 1026R.

footnote: Upgrading from the LX280 (nice machine) to the X724 was amazing. The LX280 was nice, but it would beat you up pretty badly on a rough lawn. The X724 rides like a caddy in comparison. Moving up to the 1-series is like moving from a nimble sedan to a truck.

I have a 3-pt hitch on the X724 and have spent a few hours working my driveway with a box scraper. The 1026R with FEL is much nicer to work with for general dirt moving – my neck appreciates not looking backwards half the time. When I get the 3-pt hitch parts, I’ll be able to appreciate a real 3-pt hitch position control.
I’ll take some photos after it cools off a bit outside.

Categories : Compact Tractors
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CAUTION: Disabling any feature that is intended as a safety device can subject the operator of the modified equipment and those in the immediate vicinity to an increased risk of injury or death. Please use your own best judgment when performing any safety modification to your equipment.     Note: The photos shown here are of a John Deere 1026R with a serial number beyond 210000.
You will need the following tools:

  •         10mm open end wrench
  •         Socket wrench
  •         8mm socket
  •         10mm socket
  • Small allen wrench
  • #3 Phillips head screwdriver (#2 will work as well)

Remove the lower kick panel from the operator’s station

  •         Remove the deck height adjustment knob by pulling straight up on the knob. It is friction fit; there is no set screw.
  •         For 1026Rs, loosen the set screw on the rate of drop dial using an allen wrench and slide the knob off of the adjustment rod.
  • Remove the 10mm bolt and washer from both sides of the operator station kick panel. These are the top bolts located just below the seat on both sides. Be careful not to lose the metal spacers. When you pull the bolt out it should be sitting in the well where the bolt was just removed.
  • Remove #3 phillips head screws and washers from the bottom portion of the kick panel. You’ll find these in the recessed holes on both sides of the operator’s station.
  • At this point you should be able to wiggle the kick panel free. Note that the top of the panel is tabbed and rests underneath the plastic panels on each side of the operator’s seat. The middle of the kick panel rest underneath the seat mounting platform. Set the panel aside.
  •         Optional: Take a moment to note just how dirty your machine gets in the places you cant normally see or get too.


The Reverse Sensing Switch (RSS)
In the photos below, you’ll see the switch that lets the control circuits of the tractor understand when the reverse pedal has been pressed. The lever action is such that when neither pedal is being pressed, the RSS is depressed. When the forward pedal is pressed, the RSS is depressed. When the reverse pedal is pressed, the RSS is released and the switch is deactivated. I used a circuit tracer (hey, use what you got ) to run some traces on the contacts. This demonstrated to me that the two left terminals (from referencing the third photo below) are normally connected to complete a circuit. When the switch is depressed these terminals are opened and the two right terminals are closed completing a circuit. It is also worth noting that if you disconnect the switch and switch the ignition to START, the LCD will display REVERSE SENSOR ERROR. The tractor knows to look for that switch during POST!


How to override the RSS
In theory, you could just jumper the two mating terminals on the right (from reference in photo above and the red and blue wires in the second photo below) and call it a day. However, I wanted to be able to leave everything connected and make the switch stay depressed. Here is where you can get creative. Below is what I did to accomplish the task.
I had an old piece of angled aluminum from an old garage door sensor mount. I modified it by cutting off the excess and drilling two mount holes that matched the dimensions of the screws used to mount the RSS to the bracket. The screws are 8mm with 10mm nuts. Once everything was mounted back up, the angled bracket kept the switch depressed.

I jumped up on the seat, started the tractor, activated the mid-PTO, and pressed the reverse pedal. SUCCESS, the mower stayed running!
After a little more testing, I put the kick panel back on in the same manner in which it was removed. Looks factory original, and all I have to do to enable the “safety feature” of the RSS is remove my angled bracket.
I’d like to thank an anonymous contributor that helped point me in the right direction to look for this switch. PLEASE, be careful anytime you are using your tractors and be aware that disabling any safety feature puts the responsibility on you to perform in its stead.

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