Single Field Alternator Rebuild Help!

The problem with rebuilts is you "don't know" what you are getting, literally.

So far as I know, to test the diodes, you must isolate them. It's been along time since I had a Mopar apart to check out (EDIT I see in the service manual that you indeed must separate them.)

The problem with trying to check the stator, is that they are such low resistance, you can have a partial short across windings, and a continuity check might not show that up. One thing you CAN check, if the stator is isolated from the diodes, is check the windings to the core. Should be infinate.

Also try to "wiggle" the windings. They should not move. If they do, they probably will or have, rubbed the wires together and rubbed the lacquer insulation off. You can SEE this by running the unit at night

You can NOT check these big power diodes with an ohmeter. You must run considerable current through them, and check them under load. If you have some sort of battery load tester you can put them under a short duration 20A or so load. Measure the voltage ACROSS the diode during this high loading. Should be very little drop, less than 1 volt.

I don't think much of the "book" method of a test lamp. Again, you need to run quite a bit of current through them to really test them. Otherwise you will get "false positive" results

The rotor you can check, neither slip ring should show continuity to the core. If you hook the rotor in series with an ammeter to a good charged battery, it should (depending on year an amperage) draw somewhere around 2-5A. Most are around 3, less is OK. More than 5-6A indicates a shorted turn(s) in the rotor.

Caps can be difficult to evaluate with a digi meter because the meter is so high impedance. Generally you used to set the ohmeter to either a high R scale, or the one "marked" for cap test. When you hook up the leads, the mter will "jump" to a low R reading, then slowly decay to a very high value. If you reverse the leads, the reading should be similar. Some caps are large enough to give weird readings due to a little bit of charge remaining. The main thing is that it's not shorted (low R reading) or infinity, in which case the reading won't "jump" nearly at all