In article , amdx wrote:

I'm having very intermittent lack of starter rotation on a Toyota
T-100. Over the last 14 years I have replaced the contacts it the
solenoid and more recently (1 to 2 years) replaced the starter.

For what it's worth, I had repeated problems with the starter on a
Ford Aerostar I owned - I believe the engine and starter were of
Mitsubishi origin.

The symptoms were that every three years or so, cranking would become
intermittent - occasionally slow to start cranking. It would get
worse and worse, and eventually the starter would fail to engage at
all. Sometimes, if the starter wouldn't work after the vehicle had
been stopped only for a short time, I could let the vehicle sit for a
couple of hours and it would start again.

I had to have the starter replaced two or three times during the time
I owned the Aerostar. It would always fix the problem... for about
three years... and then it would recur.

What I was told, by one of the mechanics who worked on it, was that
the starter was prone to developing a bad spot on the
commutator... I'd guess it was due to arcing. If the bad spot was
bad/burned enough, then when the starter happened to stop rotating
with this spot under one of the brushes, there wouldn't be adequate
contact and the starter would not crank.

It would probably have been possible to service the starter (open it
up and re-turn the commutator ring) and I imagine that's probably what
was done to the "remanufactured" starters I bought.