3020D electrical question

[farmall300don]

My uncles have a 3020 diesel with a 24 volt electrical system. The other day one of them had it out clearing the slush and snow off the driveways around the farm to prevent it all from freezing into an ice glacier when the temperature tanked in the afternoon. I'm not sure how long after it was parked back in the shed it was found to be on fire. They all were in their houses at the time and a relative came along and seen the smoke and alerted them. They were able to get a chain hooked to it and pull it out of the shed, where lady luck shined, as there was a puddle of water outside the door from the rain the night before and with all the snow they were able to have it pretty well snuffed out by the time the fire department arrived. I'm not sure how big the pole building is but I would guess at least 48 x 60 (maybe bigger) which they were able to prevent from going up in flames. Some believe the batteries, just installed 2 weeks ago, shorted out as the left battery was cooked down more than the right battery, and one other thinks the starter may have shorted out. I haven't seen it first hand myself just the photos that were sent to me.
I never understood the wiring system of this tractor which brings me to my question. To shut the engine down, the knob on the throttle lever must be pulled out to be able to push the throttle lever all the way up to shut it down. Is it possible that if the key was left on, that something could overheat enough to set it off? Most of the work I've done for them is replacing hydraulic lines, helping re-install the hydraulic pump, and helping replace the seals on the load control shaft underneath. My only other thought was whether the battery box was properly replaced and the battery was able to short out against the top plate as I have seen this happen on another tractor.
I wish I could provide more information but I have no idea what year this tractor was produced. All I can say is they have had this tractor for 40 years give or take a year and never to my knowledge have they had an issue like this with it before. Other than replacing the normal tires, batteries, fluids, and an overhaul or two it's been a reliable tractor for them.

 

[Bob Bancroft]

Can you tell- does it look like it's toast, or salvageable? If it's not completely toasted, can you see where the fire concentrated?

 

[Tx Jim]

Yrs back JD offered circuit breaker kit with 2 circuit breakers & wiring harness as a field installed kit just to help curtail those type of fires. 2 circuit breakers(AR47710 @ $96.94 each) are required plus wiring harness. If it was my tractor or under my repair I'd change electrical system to 12 volt system.

 

[Bob Bancroft]

It was quite a few years ago now that I rewired my 4020. Since the system worked OK, I stayed with 24V. That kit with the breakers, mounted on the starter, was part of the job. Don't you know after that I had starter trouble! If I'm remembering correctly, the armature broke. Again, based on memory, I think the center bearing was missing! Now, I'd be going to 12V.

 

[Tx Jim]

My guess is fire originated under dash. I've witnessed that same scenario several times.

 

[wore out]

If it's like most 'ol 3020's there's lots of chaff, debris, mouse mess, and leaked oil in the base of the steering pedestal, it wouldn't take much of an electrical issue dropping sparks or hot metal from above to set it off.

As to possibly leaving the key "ON" on a manual shutoff diesel, that would power up the oil and generator lights and the wiring to the light switch, nothing there that would NORMALLY be likely to catch fire.

If it still has a generator the "cutout" could have stuck shut and overheated the generator, voltage regulator, and wiring.

What is the serial number, at # 68,000 a change was made to remove the direct connection to the chassis of the center point of the series-connected batteries and instead install a 20 Amp slo-blo fuse between the center point of the batteries and the chassis.

At some point they came up with a kit to add two circuit breakers where the wing harness connects to the battery cables at the starter.

Based on those changes is seems the company must have been aware of possible electrical issues, shorts, etc. and made changes to make an electrical fire less likely, it would be interesting to know if the tractor in question was new enough to have the updates, or, if older, if the updates had ever been made.

 

[Tx Jim]

There is no "center brg" on a 24 volt starter armature or any starter armature I've seen.

 

[wore out]

(quoted from post at 04:47:18 02/18/21) There is no "center brg" on a 24 volt starter armature or any starter armature I've seen.

Jim, there may not be a "center bearing", but there IS a bushing (Key #35) in the casting (Key #22) that supports the armature shaft inboard of the starter drive.

 

[Bob Bancroft]

My memory is far from perfect, but I have worked on many DR starters which had a plate with a bushing, held in by two screws at the back of the nose cone, which supported the armature near the center. So I'm going to conclude you haven't seen many starter armatures.

 

[Tx Jim]

wore out
Thanks for correcting my "old timers" brief memory lapse!!

 

[Tx Jim]

Bob
Please forgive me for making an incorrect statement & thanks for correcting my mistake.

Having been employed by a JD dealer for 21 yrs & having served 13 yrs as a dealer service manager I seen many Delco starters disassembled.

My memory just isn't as good as it was 70+ yrs ago.
Jim

 

[tomstractorsandtoys]

Dash fires have happened to a good many 3020 and 4020's especially with the 24 volt systems. The wires get old and crack,switches go bad and often starter problems like mentioned.Battery cables also can rub through and short out. I would completely rewire the tractor to 12 volts with an alternator and a new gear reduction starter. Use heavy battery cables and plastic loom around them. If it got hot enough you might need to pull the steering valve for a rebuild. Many years ago we had a 4010 in the shop and had someone rebuild the starter. The starter had a dead short in it when returned to us and when I turned the key it melted about every wire on the tractor and the battery cables. On a 24 volt adding the breaker kit to the starter is important. Tom

 

[MSM]

Anything of mine that sits inside has either a disconnect switch or the battery cables are unhooked. To many instances of an older tractor or truck catching fire and burning down the shed.The 2-3 minutes needed to hook up the batteries is worth the peace of mind. Also doing this keeps the batteries up if there is a parasitic draw due to a bad alternator,or wiring problem. Nothing worse than going for a tractor,when you really need it and the batteries are dead

 

[WTW]

The most common cause for this "Thermal Event" Is the tractor most likely had original wiring that one of the 12 volt power lines that run between starter, generator, and switch / fuse panel were not fused at source which is the starter. If / when either of these circuits wear through and touch frame ground the wire that shorts will light up like a glowing heat element. This can also happen on a 12 volt systems. The 24 volt has twice the risk because of the double power circuits the 24 volt systems all have. Once shorted the second line can also short to ground or each other from the heat / fire due to insulation being burnt and melted from it. Get the two shorted together and now things get really hot fast!! Like stated below, replacement harnesses have both power lines fused by adding a breaker for each line at source / starter to prevent this from happening again. If replacing a 12 volt harness it too has one breaker added to protect the single power circuit for the same reasons. Call Jim at wiringharnesses.com and he will provide you with the best wiring and products for this tractor that money can buy. DW

 

[farmall300don]

I haven't been up close to get a good look at it yet. From the photos I've seen, the front end was engulfed in flames as there is very little paint left on the hood and engine and I've been told that the right front tire was burnt as well as the bushings in the hydraulic pump/crankshaft connector being burnt out. Given the age of both of them it will become a parts tractor although I have a cousin that believes his dad will take it off their hands and go at it and rebuild it. I'm hoping to get a chance this weekend and take a ride and get a close up look at it.

I appreciate all the thoughts that have been shared on this. I've spent most of my time tinkering with my dad's two 8n Fords, his Farmall C, my grandfather's Farmall H, the uncles Farmall M, as well as my Farmall 300, and IH Cub. This week has given me some food for thought as I feel now the one 8n should be completely rewired as the wiring is a mess as well as being old. I've spent the time this past summer redoing the wiring on dad's Farmall C and about half the wiring on my 300. Now I'm thinking since I have it all torn apart at the moment, throwout bearing disintegrated on me, to do the rest of it.

 

[farmall300don]

I took a ride today and looked this tractor over. Everything on the engine that was made of aluminum or rubber was completely destroyed. I would say that the right side battery went off first as the heaviest amount of damage is on the right side of the tractor and that the right side battery was melted down significantly more than the left side one was. Headlights were blown out on the right side fender whereas the left side headlights are still intact. But none the less the entire engine was engulfed in flames and not real sure about the internals of the engine. Also the right front tire was 90% burnt up and the right rear burnt enough to blow out. Couple of relatives say they would like to rebuild it but after looking at it today I would say it is good for what usable parts are still salvageable.

 

[Tx Jim]

Back before '87 when I was a JD dealer service manager I agreed to refurbish a 4020 that had burnt. 4020 with frt end loader belonged to a customer that had loaned it to neighbor to handle rd bales. After we got tractor repaired & painted I thought hyd oil leaks would never stop appearing. I can't imagine the high $$$$$ of the repair bill of a refurbishing a burnt tractor at today's part prices

My advice is let this burnt tractor go to salvage yard & find a tractor that's not a "Crispy Critter"!!!