Archive for John Deere Technical
North American Thread Types
There are many different types of threads and connectors including the North American, British, French,German and Japanese. They are identified by the geographic regions where they are utilized. Thisdocument will only address the North American or National styles of connectors.
There is a wide array of adapters available to convert one type of fitting to another. Typically, John Deere equipment utilizes O-ring Boss on transmissions or valves, JIC for hydraulic lines, NPTF on hydraulic couplers, and OFS for some cylinders.
National Pipe Tapered Thread Fuel (NPTF)
This is a dry seal type of thread; the National pipe tapered thread for fuels. This is used for both male and female ends. The NPTF male will mate with the NPTF, NPSF, or NPSM female.
The NPTF male has tapered threads and a 30° inverted seat. The NPTF female has tapered threads and no seat. The seal tales place by deformation of the threads. The NPSM female has straight threads and a 30° inverted seat. The seal takes place on the 30° seat.
National Pipe Straight Thread Fuel (NPSF)
The National pipe straight thread for fuels. This is sometimes used for female ends and properly mates with the NPTF male end. However, the SAE recommends the NPTF thread in preference to the NPSF for female ends.
National Pipe Straight Thread Mechanical (NPSM)
National pipe straight thread for mechanical joint. This is used on the female swivel nut of iron pipe swivel adapters. The leak-resistant joint is not made by the sealing fit of threads, but by a tapered seat in the coupling end.
The following is brochures and literature are the original sale brochures from the older popular tractors. This includes 2 cylinder M tractors, General Purpose tractors, Waterloo Works literature, a Modern Farming literature from 1961 showing the Deere’s New Generation tractors, A, AO, AW, B, etc. I wasn’t sure where to place some of this so I just included it all here since a couple of these deals with the 2 cylinder models.
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.