On Tue, 21 Sep 2010 04:52:03 -0700 (PDT), "Denis G."
wrote:

On Sep 21, 12:18*am, RS at work wrote:
I haven;t been around much lately as my ISP has dropped USENET, and
the Google access is annoying.

This weekend I overhauled a starter in my ex's Mercury. *My Taurus had
about 250k miles on it and still had the original starter, and the
Mercury has the same starter yet it had to be rebuilt with 105k. *When
I pulled the starter it had a sticker showing that the starter was
remanufactured.

Upon disassembly, the brushes were shot, but the bushings and the
armiture looked great, so it was a simple matter of cleaning and
installing the brush holder and the ex had he car back in service.

I find several things curious here. *First this car had the starter
fail at least twice in 105k miles yet it is the same kind of starter
that went 250k miles.

Next, the failure of the brushes in the reman (starter #2?) failed,
yet the commutator was in pristine shape.

Any of you have any speculations why this would happen?

Also why is it so dammed hard to find overhaul kits for starters?

There are probably many formulations of the materials used in making
carbon brushes as well as differences in sintering temperatures,
pressures, furnace atmosphere, etc. In addition there are cost and
quality issues involved in the manufacturing of these products. I
don't think that there is an simple answer to your question.
http://en.wikipedia.org/wiki/Brush_(electric)

I'll second that faulty brush probability. When a vehicle is out of
tune, longer cranking times could account for that as well, halving
the useful lifetime.

How were the bushings? Premature wear there creates extreme drag and
increases the amperage going through those brushes.

--
Some people hear voices. Some see invisible people.
Others have no imagination whatsoever.