Charging problems

[larrylarkin]

Wondering if anyone else has had the same problem and solved it. Last week I drove to Tx and Ok. On the way to Ok my battery went dead and I lost all my electrical power. I made it to Bixby and went to the auto parts store and had my battery checked. Was told it was bad and bought another one. The next morning I started out before daylight coming back to Alabama. Made it for 45 min and the battery went down. I waited until daylight and drove on to Al. without a charged battery. Next day (I charged the battery overnight) I determined it might need a new alternator.
I pulled it off and took it to have it checked and the auto parts store told me it was ok. The brgs are bad in my alternator so I decided to change them. I started tearing down the alternator and found one brush was almost used up and where it had been running on the armature there was a deep grove in the armature itself. Is it possible that it stopped making contact and someway by taking it off and carring it to the auto parts store it got jarred and started making connection again. BTY I have a new alternator on order because even if it is charging now it is short lived. The auto parts store man told me if there is a short in the small wire coming off the alternator it will not let a "diode" or "relay" to open and allow the alternator to charge. It is on a 1995 300e diesel.
Thanks for any input!!
L L L

[Gilly]

Yes, absolutely, very common. The simple "on the road" repair is to replace the voltage regulator. The old one can be retained and the brushes replaced to be reused later. Or just toss it.
There is some theoretical limit to how deep the grooves can go, but I am not certain how deep it is. If the alternator suddenly craps out, the #1 thing to do is remove the regulator and see if one of the brushes is bad.

[larrylarkin]

Thanks for the input Gilly!
The new alternator did the trick. Evidently the brush was not making contact with the armature and did not charge. After taking the alternator off and jarring it around somehow the brush made contact and that was why the auto store man told me the unit was good. (The grove in the armature was almost too deep to turn down in a lathe and the brush was wore almost out.)

[david s poole]

can't believe that the guy in autoparts store after you told story didn't undo two screws and check the brushes.