Alternator Woes

[Bill90Loyale]

90 Loyale, 208K miles. Great shape except I've been dumping a ton of cash into the stock Hitachi alternator. Call me stupid, call me a sucker, just don't call me late for lunch. Here's the basic history:

1. Two years ago, had the alt overhauled by local alternator shop. Preventative maintenance. Brushes etc. (about $70).

2. One year ago, diodes in rectifier failed ($70).

3. Two months ago, stator failed ($70).

4. Yesterday, rectifier failed again. (alt is back in the shop).

 

If you knew this shop, you wouldn't rag on 'em too much. Salt of the earth honest as the day is long (80 year old mom and her two sons). Been in business forever.

 

What I wanna know: Any thoughts on what might be causing the failures in this scenario?

[Cougar]

Have the battery checked out and make sure it is ok. Also check the check the amount of voltage drop between the alternator output and the positive post of the battery with a good load on the system. Also check the grounding between the negative post and the engine the same way. You shouldn't see more than around a 0.2 volt drop on either line. If there is a bad reading on the positive side check the fusible links first for a bad connection. The black fusible link is in the charging circuit.

 

I'm not sure how economical it is to have the alternator repaired. You should be able to get a rebuilt Bosch unit for around $150 dollars that will have a lifetime warranty.