Actually folks there is basically nothing wrong with these ammeters. They are after all 40+ years old and require maintenance. What happens is the fibre insulators dry out and shrink. When that happens the terminals become loose inside the gauge.
It sounds like you know a lot more about thi than I do. That being said, my understanding is that the bulkhead connectors that feed the ammeter gauge were designed to be barely up to snuff when they were new, and that 40 years of age, corrosion, etc. make that problem even worse.
The other reason I say that it's a bad design is that ... it can cause the car to catch on fire
When a voltmeter fails, you just have a non-working gauge.
Still, I think you're right that they can be overhauled and made safer and more reliable, but I personally would rather just do away with the ammeter and have a voltmeter. A lot safer, a lot more reliable from an overall vehicle perspective. When my ammeter failed I was on the road, at night, and I suddenly no power to anything, including headlights or hazard flashers. I didn't have a fire, but it was still not fun.
