About 25K miles on the last rebuild, and I notice the idiot light glowing noticeably brighter than usual during major power draw (brights/radio/OD pull-in). Also, ran battery near flat recently (been neglecting routine charger use). Belt is tight, so unless there is a regulator issue (?) likely new brushes are overdue.
Curious, what kind of mileage are others getting between gen. rebuilds?

6 VOLTS/POS. GRD. NW INDIANA

Daniel,
'Tis more "complicated" than most folks think: Brushes come in many different compositions of carbon and (sometimes) copper or other alloys/mixtures.  This effects electrical conductivity, and wear of both brushes and armature commutator.  I do not know the specifics of your generator brush needs - if still an "original" Ford generator, try to find the exact brushes specified for that particular generator; and, they should give you the best over-all generator/brush service. Remember, though, that (generally) longer-wearing brushes will mean more/faster wear of the commutator (which would you rather replace/service?). OR, find an "old-fart" generator rebuilder in your area (getting more and more rare these days) for the "right" brushes/guidance!

Regards, JLB

55 Ford Crown Victoria Steel Top

25,000 might well be getting there, though can try pushing in the brushes at idle (carefully!) with a wooden tool or a popsicle stick. Sometimes they get stuck or hung up catawampus in the holder. Fresh full length brushes have higher tension against commutator.

I assume then that if reduced brush-commutator tension results in significant lowering of gen. output, and if that’s the case (they are not hanging up), then letting them wear down past the nubs may likely damage the commutator. Guess it’s time to ‘bite the bullet’, and finally get around to rebuilding my backup 40A /OEM gen.

6 VOLTS/POS. GRD. NW INDIANA

I have run into a few rebuilt generator issues that have turned out to just a broken or weak brush spring. Even one that a rebuilt myself the replacement spring lasted no time, more off shore crap

Don't ignore the regulator as there is just as good a chance this could be the problem. What is the system voltage at idle? Voltage with increased rpm? Shop manual lists system voltages along with how to perform  a full field test to check if the generator is capable of a good output. Often the regulator contacts will develop a powdery oxide requiring a touch with a piece of fine emery and a hit of contact cleaner wont hurt either. Do you have a known good spare regulator on hand? Hope this helps, JEFF...........................


64F100 57FAIRLANE500

Also, if you replace the brushes again, when you clean the armature area, use a very fine sandpaper(2000-3000 grit) and spin the armature to insure a clean and smooth surface.  Use a very small knife/awl and clean the grooves of any old carbon from the brushes, and blow dry.  Make sure the new brushes come all the way out of the holder with spring tension, so that they can seat fully as they wear.  If they don't, stretch them slightly, but carefully until they do.  Reassemble and make sure the polarity is correct.  Check the voltage as suggested above and clean the points.  Joe-JDC

JDC

Correction to my previous post: Use sand paper, not emery paper when dressing contacts.  Thanks Joe-JDC for the reminder.


64F100 57FAIRLANE500

I’ll start with swapping regulators (simplest approach) and take a nighttime drive to see if the gen. light is dimmer under heavy current draw. If no difference, then I’ll get out the manual/voltmeter and proceed from there. I’m familiar with rebuild routine (done a couple), and have some pre-Asian brushes and a NOS commutator put away just in case. Hope the endplate bushing is still good though.
Thanks for the help.

6 VOLTS/POS. GRD. NW INDIANA

Update: Installed my back-up regulator....problem solved! Gen. light totally dark now under full load (radio, brights, heater fan full blast, accelerating in underdrive), except for just the very faintest blink when the OD hold-in coil activates for that micro-second before the pull-in coil releases. Regulator points don’t really look burnt/corroded, so I’m assuming it just went out of adjustment over time. I COULD clean it up, get out my voltmeter and try to adjust it, but since it is old/worn and regulators are relatively inexpensive, I’ll likely just order another new backup and be done with it. Too bad there isn’t a 6V solid state model available that would be an OEM/bolt-in fit.

6 VOLTS/POS. GRD. NW INDIANA