Sounds like regulator is over heating This is why i had my local guy rewire my alt to a internal regulated one wire style. And i never looked back....
I could not disagree more. The 70/ later style regulators have been VERY reliable over the years. Only problem nowadays is getting good quality, non--Chineseo replacements.
There is no inherent reliability increase with these so called internal regulator conversions (actually they are externally mounted on the alternator) and since these are NOT a factory standard part, good luck getting one when you need it
Get a new regulator...OR..Get a square back and an electronic regulator, its just one more wire..
He SHOULD already have a square back AND a 73 already has an electronic regulator
But before you replace anything, CHECK a couple of things.
Pull the alternator off, and check the condition of the BRUSHES. They could be greasy, sticky, or just worn.
Pull the regulator and your ignition box off, and scrape clean under the mounting ears and around the firewall where they mate. Remount using star washers for grounding, AND as someone else on here suggested, "daisy chain" a ground wire of no12 from the block to the regulator and to the ignition box mount bolt
The reason Pishta suggested a "square back" is that they are better for low RPM output.
Square back / round back: Round back is an older design. ALL pre 70, grounded field (incorrectly called "single field") are "round back
Square back was 72? and later. IN 70, the round backs were "isolated field", as are all square back, incorrectly called "dual field.". To further muddy the waters, rebuilders many times drilled a hole in the rear of a round back 69/ earlier, and added a second, isolated brush holder
This thread shows the differences:
http://www.forabodiesonly.com/mopar/showthread.php?t=187013
If cleaning the grounds and inspecting or replacing the brushes does nothing, remove the green field wire at the alternator and install a clip lead from the exposed alternator field terminal to ground. This SHOULD cause full output. Start the engine, and gingerly raise the RPM. It should charge more as the RPM goes up. If you get the ammeter far to the right, ease off to prevent over--voltage. If this seems OK, you either have a bad regulator or a wiring problem in the field circuit
To check that out, go up to the regulator connector and inspect. Look for looseness or corrosion. Work the connector in/ out several times to scrub the terminals clean, and to feel for tightness.
Then devise a method to jumper across the two harness connector terminals. Go down to the alternator. Remove your clip lead, and reconnect the green lead. Now remove the blue field lead and install the clip lead from that alternator field terminal to ground. Once again, run the engine up, watch the ammeter, and it should show full output.
If so, the wiring is probably OK. At that point I'd replace the regulator.
