Your '48 8N came from the factory with a ballast resistor on the back of the dash panel like in the photo. It allows full current at startup and as it gets warm it increases the resistance to extend the life of your coil. The resistors you are talking about are probably little white rectangles...
I got mine from my local Agco dealer. I had to measure the internal width of the bucket because it bolts to each side of the bucket and then drill the holes for those two bolts when I brought it home.
I am also only familiar with a 3-wire voltage regulator on 8Ns. Perhaps the 4th wire grounds it? That said, you really need to know which terminal is which because you can immediately ruin the regulator if you touch a jumper wire to the wrong terminal. You usually take a short wire and just...
You can make sweeping turns with ground-engaging implements, but sharp turns with the implement in the ground will break things on Ford Ns. Ford beefed up the upper lift arms with my model but I still lift plows, cultivators and disc harrows when making turns.
I'm not familiar with the term "third function" but, when I bought my MF-1533 new in 2006 I had the dealer install remote hydraulics so that I could operate my hydraulic toplink. Hope this helps some.
As John suggested, start with the top cover and check the piston. The factory piston had 3 steel rings. Rather than a ring job on it, I would replace it with a piston from the '53-54 NAA with an o-ring and leather backup washer. It will seal better. Also take a hard look at the cam follower...
Sure it is. 8N hydraulics, when working properly, can lift ~800 pounds and it will lift all three implements you listed above. Parts are easy to get and how-to information is available at some websites and on YouTube.
Yep. You can learn all you want to know from this compilation of photos and restoration info in this document: https://www.ntractorclub.com/manuals/tractors/An Introduction to the Ford Tractor 2N Warhorse, v06-09-16.pdf