MF 40 Neutral Safety Switch and wiring help

Billmac

New User
I launched into a project to get my old MF 40 with a front loader to charge. After putting it back the way it came and hooking up the exciter wire the way the electrical man told me, not I can't even get it to crank. I suspect I may have disturbed one of the wires relating to ground or unplugged the wire from the neutral safety switch. I actually own one of the worthless shop manuals that has no information on electrical systems.
So I plead your help for a location of the safety switch and possible routing of the wires, and if there is a wiring diagram for a one wire alternator, I would appreciate that also.
I still have not determined where the negative battery cable is attached after looking for 30 minutes. If you have ever worked on one of these, you know that everything is hidden under the manifold, carb, or frame. You can't get to the starter solenoid until you take all this stuff off. I'm probably going to cut off the ground cable, put a new one on, and attach it to the frame where I can see that it is secure. I thought I had seen the neutral safety switch years ago, but that was probably on a different tractor. If you know where it is and how to get to it, PLEASE HELP.
Bill
 
I launched into a project to get my old MF 40 with a front loader to charge. After putting it back the way it came and hooking up the exciter wire the way the electrical man told me, not I can't even get it to crank. I suspect I may have disturbed one of the wires relating to ground or unplugged the wire from the neutral safety switch. I actually own one of the worthless shop manuals that has no information on electrical systems.
So I plead your help for a location of the safety switch and possible routing of the wires, and if there is a wiring diagram for a one wire alternator, I would appreciate that also.
I still have not determined where the negative battery cable is attached after looking for 30 minutes. If you have ever worked on one of these, you know that everything is hidden under the manifold, carb, or frame. You can't get to the starter solenoid until you take all this stuff off. I'm probably going to cut off the ground cable, put a new one on, and attach it to the frame where I can see that it is secure. I thought I had seen the neutral safety switch years ago, but that was probably on a different tractor. If you know where it is and how to get to it, PLEASE HELP.
Bill
Welcome to the Forums

Look for the neutral switch just ahead of the transmission cover right front corner.

I don't see that you have said if it is gas or diesel. You mentioned you hooked up the exciter wire the way the electrical man told you. An exciter wire indicates you have a three-wire alternator, internally regulated. The parts book shows the 40 as using a Delco 10DN externally regulated alternator (used before the internal regulated alternators). Does your tractor have an external regulator for the alternator? You ask if there is a drawing for a one-wire alternator, are you looking to do a conversion? The answer to that is not OEM as they didn't have one-wire alternators. As for the wiring diagrams, I expect they are in the Operator's Manual. Massey Ferguson often put those in the Operator's Manuals, not the shop/service manuals during that time frame. I don't have a manual for a 40, but may have one similar depending on what you are looking for and need for wiring info.

Here are the three Types of Delco alternators, which do you have now?


10DN.jpg10 or 12SI three wire.jpgDelco 10SI 0r 12SI one wire.JPG
 
I launched into a project to get my old MF 40 with a front loader to charge. After putting it back the way it came and hooking up the exciter wire the way the electrical man told me, not I can't even get it to crank. I suspect I may have disturbed one of the wires relating to ground or unplugged the wire from the neutral safety switch. I actually own one of the worthless shop manuals that has no information on electrical systems.
So I plead your help for a location of the safety switch and possible routing of the wires, and if there is a wiring diagram for a one wire alternator, I would appreciate that also.
I still have not determined where the negative battery cable is attached after looking for 30 minutes. If you have ever worked on one of these, you know that everything is hidden under the manifold, carb, or frame. You can't get to the starter solenoid until you take all this stuff off. I'm probably going to cut off the ground cable, put a new one on, and attach it to the frame where I can see that it is secure. I thought I had seen the neutral safety switch years ago, but that was probably on a different tractor. If you know where it is and how to get to it, PLEASE HELP.
Bill
This is the neutral safety switch on my 165.
 

Attachments

  • Mf 165 safety switch.jpg
    Mf 165 safety switch.jpg
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Hi Bill,
I have a parts book for a Massey Ferguson 40 tractor. It shows a good break down of the different parts of the unit and how stuff goes together.
Not sure if this would be useful to you. I would sell it if you are interested.
 

Attachments

  • Screenshot 2024-03-27 at 9.41.02 PM.png
    Screenshot 2024-03-27 at 9.41.02 PM.png
    2.8 MB · Views: 9
Hi Bill,
I have a parts book for a Massey Ferguson 40 tractor. It shows a good break down of the different parts of the unit and how stuff goes together.
Not sure if this would be useful to you. I would sell it if you are interested.
Wrong parts book for his tractor. He has a Massey Ferguson MF 40 industrial tractor, not a Ferguson 40 which is the manual you have.
 

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