[GearHead33]

So, like the title says I've gone through 3 alternators in a month. I replaced my original alternator after 127,000 miles when the charging stud snapped off (no idea how this happened). I had one new alternator from autozone, bad regulator, then 2 alternators from rockauto, 140 amp Ac Delco new units, bearings in both of them have gone out fairly quickly. What could be causing this or is it just my s*** luck? I'm getting really tired of replacing these damn things.

 

[cocobolo95]

If it was the electronic parts of the alternator failing, I would chalk it up to bad parts. But the bearings failing, I would look at too much tension on drive belt, or misalignment problems. Also check alt for not having any movement when bolted up.

 

[GearHead33]

I dont think it would be an alignment problem since my factory alt lasted for 18 years and the bearings in it were fine when it went out. What is the best way to check for alignment? I still have the stock tensioner, could it be getting weak and leaving too much slack causing bearings to wear out?

 

[Racy Roadmaster]

Bearings wear out when there is to much tension on the drive belt.
I doubt that you are getting brand new alternators from Autozone or elsewhere. You are most likely getting remanufactured /rebuilt units from these places. A suggestion could be to replace your tensioner, I believe GM still makes new tensioners, If you are interested ,I have a good one
with about 50k miles on it from my roadmaster. A new Delco alternator from GM will cost you about $450 dollars. If you dont like the sound of that then I would bring you old alternator to a local starter,alternator ,generator rebuild shop,where they have people
repairing units that actually know alot about what they are doing! ed