I was driving back to the farm with a load of corn and i smelled and saw smoke. This truck had been leaking coolant so i thought it had overheated.
Pulled over and raised the hood and didn't see anything wrong, called the boss and told him the truck broke down. About 30 seconds after that one of the hydraulic hoses started pouring out smoke as thick as you can believe and right after i got the extinguisher it burst into flames.
Turns out what it was, the pos battery cable (about 2/0 hooked to FOUR group 31 batteries...) had been laying on the frame all these years and the insulation finally wore through. The initial smoke i saw was the engine-chassis ground frying. After that the cable must have lost the ground where it was laying on the frame.
After i raised the hood and got back in the truck it must have moved back, and all the power didn't have anywhere to go, so it turned the steel braided steering hose into a ground cable. The smoke was the rubber burning off as it got hot enough to ignite the oil in the line.
Thankfully, not much was damaged and i saved the truck. It needs a few wires, 2 cables, 2 or 3 hoses and 2 plastic lines to the air compressor.