[Kurt in NJ]

To me completly dismantling is removing the field coils ---this doesn't need to happen

I doubt you can get enough heat to the connection to properly solder it without taking the armature out, and you need a good sized soldering iron, too small of an iron will heat things too hot and chance of damaging insulation, at least a 3-400 watt iron, I use a 600 watt iron and it heats the junction in a few seconds(about5) to soldering heat, this way the heat doesn't travel too far ---a long time ago I used 2 150 watt guns, the insulation was smoking some after the 30 seconds to a min it took to heat and everything got hot.

There used to be a replacement "stud" that fit over the stripped one( try the "HELP" brand at auto parts store), but if you have to go in you might as well replace it with a new one ---and remember that you want new nuts too, the power flow is from the stud to the threads--then to the side of the nut to the terminal ----and if a washer is used it can't be corroded too ---rusty nuts could have been the start of your problem