The insulation on the wiring in my JD 490E has gone south as confirmed with a wire megger. The wiring is bundled and generally lays on the bottom of the operator's deck. It takes signals from the various sensors and through the computer, it tells the hydraulic controls of the main pump what to do. Over the years many hoses have been failed, and the hydraulic fluid has drenched most all of the wiring. I researched the problem a bit on the net and found out ALL petroleum products leach the plasticizing additives out of the PVC insulation on the wire. Exposure to any petroleum product, over time, and particularly with elevated temperature, causes the wire's insulation to crack, thus causing faults which might come and go with the vibrations of the operation. When it becomes advanced, as in my machine, it starts killing sensors and solenoids, resulting in jerky, stalling, and overheating behaviors. I tried to find a new wiring harness for the machine, but it is no longer available. During my research I found that wiring insulation standards have changed over the years after it was recognized exposure to petroleum was having this effect. The current highest standard petroleum resistant wire is AWM 21098. This wire is coated with a clear sleeve which isolates the insulation from the petroleum products. The sleeve extends the life of the wire's insulation, but is not a cure all for the problem. My question is, "Has anyone else experienced this problem, and if so, how was it solved?" Matching all the wire colors when re-wiring would probably be impossible. I am considering using multi-paired, individually insulated conductor wire covered with an outside insulation sheath. Any and all experience and solutions shared will be sincerely appreciated.
I have had to replace wiring harnesses due to oil soaking taking out the insulation but I have never had to fabricate a major harness nor could I tell you the best way to go about it. I’m guessing the way to start would be mark and remove old harness, clean it, lay it out on table, and build a new harness to match it size wise and then according to schematic. I also wonder if there is an outfit that will custom build if given the schematic and specs needed.
I work on lots of old junk now for a friend and see that stuff happening all the time. No way to stop it and the stuff I’m working on isn’t worth the cost of the harnesses. I just find the problem areas and wire around them if possible. If not I modify something to make due. If you don’t have enough revenue to pay the expenses, then the machine is dead.
Knivens894, Pain & heartache. Sounds like you know what the solution is. There are places that can build you a custom one, as per sample, but I’m sure it will be stupid expensive and long turn-around. I’ve built some nice custom harnesses using Deutsch DT connectors. Good golly, it’s time consuming.
( twist 2 wires together and call the insurance company ) no , like said above try to just fix it
If the wires are fine, but the insulation is cracked, you could fix sections by pulling the loom apart and using electrical tape, lots of electrical tape. Won't be fast, but it might get you going easy if the sections are limited, you can get at them, and you know which wires are sensitive.
Don't forget the "liquid band aid" for wires, I have used it many times after having to probe through the insulation or where something has rubbed through insulation before turning green...recently used same product for house wiring (4 coats) after discovering a critter chew before buttoning up a repair til springtime rebuild will take care of issue permanently....
Love that stuff. It’s considered airfreight hazmat, so I don’t take it on my adventures.
The good ole days when the only thing electrical on heavy equipment was a few lights. And a magneto.
I do a lot of electrical/electronics work. Fixed many harnesses. You probably know your options best being able to see it, but if only the oil soaked area has failed, I have soldered in spliced pieces. Basically cut the bad section out, and solder new wire into it. If you want to do this right, you may actually need to remove the harness from the machine. I would never do that job with those little solder spices. I would do them proper with an iron and solder, you can 100% buy all the colors you desire but prob a large spool of each. numbering wires is an effective method rather than colors. All splices get glue shrink. You can add bandaids if you want but good wire in hot oil will survive. Go ask Allison what they use.
Planned obsolescence, wiring disintegrates, No Longer Stocked and machine is then a worthless chunk of scrap.
Have you tried looking up a harness for a slightly newer version of the 490 that might still be available and could be modified to work on yours?
We use the same 600v oil/gas resistant machine tool wire we use on panel builds. I just did some senders on a truck with it then they blew an oil line a few days later, hot oil turned split loom to mush but left the MTW alone.
I have used Teflon insulated wire for the toughest jobs. It’s expensive and a little harder to work with, but that stuff won’t break down ever, and it’s really sturdy stuff.
Injector harness wire/type-There are Series 60's out there 30 years old that have never had a issue cooking in 205 degree 15 x 40.