Ford Alternator bearing failure

[samiam88]

Hi, the alternator on my Ford E250 seized today. I replaced it with a brand new unit and within 40 miles the new one also seized. The auto parts tech said that this problem is due to the alternator not being grounded well enough. He claims that if I run a new ground wire from the alternator to the engine that it will fix the problem. He claims that the aluminum bracket that the alternator is mounted on is a dissimilar metal from the steel engine block which will cause corrosion between the aluminum and steel not allowing the alternator to ground properly, consequently, this overheats the bearings causing them to fail.
Does this make sense to anyone???

[FlamingTaco]

Yes, this does occur. You replacement alternator, though, should not have failed within 40 miles. Take it back.

[samiam88]

Thanks for the reply. Many people that I have talked to have said the same thing that you did. The parts store replaced the alternator and I installed it along with a ground strap from the alternator to the block. I also ran another ground strap from the block to the chassis just to be sure. Hopefully, it will solve the problem............... I am getting tired of changing it, it is a pain in the #$!@

[freeclimber]

Isn't the ground strap a "dissimilar metal" from the aluminum body of the alternator?
I say clean the mating surfaces well (more surface area to make contact than the ground strap connector) and call it good.
I also agree that 40 miles of service =junk part.