Durlast alternators

Could be an intermittent problem with the alternator. If that happened to me, I’d put a volt meter in the passenger compartment monitoring the battery voltage so I could see it while I was driving. I’m guessing the alternator voltage was intermittently dropping below 12 volts, causing the dashboard battery warning light to turn on. Not necessarily a faulty alternator btw, could be a slipping belt.

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George, I changed the belt out before and no fix. Like i said I had it tested multiple times and it passed. I plan to take it to an auto parts store and test again. Maybe even might have it repaired too.

You might check the alternator pulley to make sure it’s getting a good bite on the belt. With the engine off of course, put a wrench or socket on the alternator pulley nut and try to rotate the pulley against the belt.

It should be difficult if not impossible to move the pulley against the belt.

I am huge fan of junk yard alternators for older cars. I typically have way better luck than store brand alternators. And they are much cheaper.


If the failed alternator is in a car that I depend on for reliability, or if the alternator is in a labor-intensive place to remove-and-replace, then I’ll pay the money to buy a good alternator. There’s a good automotive electric shop nearby that does quality rebuilding right there.

Otherwise, if I have time, I’ll rebuild it myself or I’ll install a less expensive Duralast brand. A few years back I installed a lifetime Autozone alternator where it took three alternators before I got one that worked. That was only that one time.

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No I’ve checked that, it was fine. I’m pretty sure the old one the voltage regulator was going bad. Anyway, seems the duralast is preforming well.

Any idea what a shop might charge to rebuild an Alternator?

Hi John:
I do not. Call places in your local area.

Somewhere between affordable and outrageous.

Ha, you’re probably right on that one

Depends on the alternator and what needs to be done. If all that’s needed is to replace the brushes, probably around $30. Bearings needed too? Around $60-$75 for brushes and bearings I’d guess. Diodes too? Maybe $100-150 for brushes, bearings, and diodes. If there’s a problem with a circuit board, or the case is cracked, probably not $$ -wise affordable compared to just buying a new or off-shore rebuilt one. I expect in most cases just replacing the diodes or just the brushes will be all that’s required.

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Plan to take it in when I get the time. Interesting enough I took it in to autozone and it passed their test 4 different times so maybe the connecter was causing the light to trip.