Evaluating a previous 12v conversion on a 4020

belaw

New User
As I mentioned in another thread, I recently purchased a '68 4020 that was converted to 12v. There is a single 12v 4dlt battery, negative terminal grounded to the frame. I haven't spent enough seat time to know of any problems, but whoever performed the conversion took some shortcuts: the fuel gauge was un-wired; the wiring to the lights was disconnected and the key was removed and replaced with a simple toggle switch.

Can some of you guys who have performed 12v conversions guide me on what I need to check out on the conversion on this tractor? Are there any specifc problem areas that I need to look for in a 12v conversion?
 
I wouldn't say so. It sounds like your biggest challenge is what was done by whoever was there before you.
Did they cob the old harness, run individual wires, or what?
The best place to ground the battery is right back to the starter frame.
 
Be sure that both the brown & blue wires in the harness(original 24V) at the starter are attached to the top post on the starter solenoid. I would also install the extra starter relay if one already wasn't there.
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(quoted from post at 10:47:41 03/05/13) I would also install the extra starter relay if one already wasn't there.

Okay, I'm going to show my ignorance of diesel and/or tractor electronics, but what does the "extra" starter relay do? Where does it go- between the battery and solenoid?

Maybe I'm stuck thinking in terms of automotive electrical systems, but I just can't figure why you would need a relay in addition to the starter solenoid!

Brian
 
The starter relay that JD adopted for later model tractors relieves some of the elect. load on the ing & neutral starting switches and allows for more amps(voltage) to be transferred to the excite wire(yellow colored) on the starter solenoid IE better starter operation. Here's an example of a relay kit but it came out of a JD utility parts catalog instead of a rowcrop but the principle is the same.
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TX Jim is 100% correct as the second starter relay makes a big improvement. I converted my 3020 and it intermitantly would just click. I spent hours going through all the contacts with minimal luck. I then put in a second relay and it starts every time now. I think the contacts get enough corrosion after 40 years and just won't carry the load as well. I did the same thing to a 2510 and it made a big difference there too.
 
(quoted from post at 17:21:15 03/05/13) TX Jim is 100% correct as the second starter relay makes a big improvement. I converted my 3020 and it intermitantly would just click. I spent hours going through all the contacts with minimal luck. I then put in a second relay and it starts every time now. I think the contacts get enough corrosion after 40 years and just won't carry the load as well. I did the same thing to a 2510 and it made a big difference there too.

So the point of the "extra" relay is to make sure that enough juice flows to trigger the solenoid when the starter button is pressed? I need to keep telling myself this isn't a small block Chevy....

Is there a specific relay recommended for this application, or will your basic automotive cube relay handle the load?

Brian

P.S. This forum is great!
 
Correct. I don't remember what amp rating of a relay I bought but the heavier duty the better considering it's a tractor.
 
JD uses the standard old Ford truck starter solenoid. Attach it to the starters own solenoid with a worm gear clamp.
 
(quoted from post at 20:27:13 03/05/13
Is there a specific relay recommended for this application, or will your basic automotive cube relay handle the load?Brian

Actually you can get one from a JD dealer fairly reasonable.
RE170320 KIT, STARTER CIRCUIT RELAY ADD 28.37 USD
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John Deere uses the Ford truck solenoid in the conversion kits. They are <15$ from any autoparts store last I checked.
 

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