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Last update 12/09/2010

"Just say No" to Rebuilt Auto Electrics


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I have long advocated buying new replacement parts instead of "rebuilt" or "remanufactured" parts.  Reman parts used to be OK.  Then the Wall Street types invaded the industry and things went to hell in a handbasket.

A couple of years ago I got caught out on a trip with a bad alternator.  I could not find a new part so I opted for an AutoZone rebuilt special.  I had barely gotten home when this one quit.  Before returning it, I decided to open it up and take a look-see.  Glad I did.  This is a perfect example of why one should NEVER, EVER buy a reman part.

Remans rejected since 05/23/07 
Here is the view of the rectifier end bell.  If it looks sand blasted, that is because it has been.  The standard procedure now is to disassemble every alternator that comes in, dump the parts in the sand blaster and blast away.  Note that the condenser has been blasted.  Real good for long life.  Grit was even found in the bearing grease.
Here is the reason the unit failed.  This is the positive output stud.  There is supposed to be an insulating washer under that stud.  If there ever was one it is gone now.  Note the sand blast damage and the rust.
A view of the brushes.  Even though there is less than 1000 miles on this alternator, the brushes are worn out.  Or more accurately, they are the brushes that the alternator had when it arrived at the reman shop.  
Another view of the output stud.  From the scratches on the aluminum I would guess that there was an insulator there but that it didn't get put back in after the "reman".  
The stud removed
The stud itself.  Note the burnt plastic under the red part.  Also note the rust.
  Here we get a good view of the stator.  The "reman" process involves applying a high speed sanding drum to the stator poles.  This does a couple of things. 

First it shorts the laminations together (green arrow), causing higher eddy currents in the stator and more heating. 

Second, when the operator slips, it removes the insulation from the windings (red arrows).

Here we see the slip rings.  Looks like one got in the way of a hammer!  That lump works wonders for brush life!
I'm not sure what all is going on here, as the field has been subjected to the black paint treatment, AKA "overhaul in a can".  The winding looks and smells burnt but I'm not sure if that is the paint or the actual winding.
A final overall view.  Again one can see the massive sandblast effects and the worn out brushes.

It did look purty from the outside, though, what with all that sand blasting and the silver paint and all.

Do you want to rely on something like this on your next trip?