"Elle" <honda.lioness@nospam.earthlink.net> wrote in message
news:mYnHf.13902$rH5.21@newsread2.news.atl.earthli nk.net...
> "Michael Pardee" <michaeltnull@cybertrails.com> wrote
>> "Elle" <honda.lioness@nospam.earthlink.net> wrote
>>> "Michael Pardee" <michaeltnull@cybertrails.com> wrote
>>>> I was lucky that both my cars that had that problem also had
>>>> voltmeters. I noticed the voltmeter in each fluctuating as the brushes
>>>> made contact and then didn't, but the lamps never flickered. (Sometimes
>>>> they wouldn't come on before start-up when the brushes were wearing
>>>> out.) Talk about "idiot lights!"
>>>
>>> Would you say watching the voltage across the battery terminals of an
>>> idling car might also likely pick up bad brushes?
>>>
>> That's how I caught it in both cases. The voltmeter fluctuated sharply
>> between charging and battery voltage. I think the movement of the meter
>> caught my eye as much as actual dash scanning did. At first it was only a
>> couple seconds dropout at a time, worsening to a minute or so good and a
>> minute or so bad within a week. In both cases the dropouts were worse
>> when cold.
>
> I want to make sure I understand. These cars had a built-in voltmeter on
> the dash, and it was oscillating more than usual? Then you also took a
> portable voltmeter under the hood, connected it to the battery terminals,
> and watched the voltage at the battery terminals vary?
>
Exactly right. The meters would show charging voltage (they weren't
calibrated, of course, but we get used to what they read with the engine
running and see what they read before starting) some of the time and
not-charging voltage other times. That got my attention so I checked the
actual voltages at the battery to see if the charging really was
intermittent. Normally the meter in either car would be pretty steady until
I turned the lights or the heater blower on - then it would only drop a bit.
These were big changes.

> I have started a site on "Battery & Alternator Tips" and want to include
> this or similar.
>
> Doug, I saw your post and agree there is at least a small advantage to
> going to the alternator itself for measurements to identify bad brushes.
> However, I am trying to devise some quick and dirty checks (if they exist)
> a layperson can do to identify likely failed brushes.
>
> Draft: http://home.earthlink.net/~honda.lioness/id13.html
>
> (Not to supplant Tegger. His site is way more comprehensive. I am
> anticipating pre-emptively replacing my 91 Civic's brushes in a year or
> so, so I'm writing this up as much for that.)
>
Looks good so far, Elle.

I'm sure if the Volvo and the Nissan didn't have dash voltmeters I wouldn't
have known anything was wrong until the battery gave me real trouble. I
suppose I might have been lucky enough to see the headlights dimming a bit
once in a while, but I dunno.

Mike