Alternator failure -- twice!

Heat and poor quality alternators. My old Pontiac used to burn up a $60 alternator every year for years until I got tired of replacing them and got a $180 alternator. That one lasted the remaining life of the car, about 6 more years.

There is an auto electric shop about a mile from me. Alternator, or starter motor, I always take them to that shop and let them rebuild them for me.

I've been told that things that cause problems include bad grounding of the alternator and bad batteries.

The battery was replaced at the same time as was the alternator: 5 months ago (corrected from my original post). 

Measurement of battery cables: from battery cable (+) terminal to alternator (+) terminal: 1.5 ohms. From battery cable (-) terminal to chassis: 1.5 ohms. 

Charging numbers with new alternator & 5 months old battery: With partially (50%?) depleted battery, when the car was started and engine revved, the new alternator output 34 amps, headlights off. With lights on high, output was 44 amps. Charge voltage was 14.04 volts. These numbers are within those specified in the Toyota factory manual (charge current: ³30A or more²; charge voltage: ³13.9-15.1². 

Thanks.

Take the thing to a small rebuilding shop, and ask them about the quality of the winding material that was used.

There is a big difference between a rebuild using high temperature wire and some crappy Autozone rebuild using undersized varnished wire.

--scott

but if it's a junky alternator to start with aren't you still going to have a junky rebuilt alternator

what do they do when they rebuild one?

Possibly. If so, they'll probably tell you it's not worth rebuilding.

They take the whole thing apart and check all the individual parts. They replace all wear items like brushes, bushings, and bearings. If a winding is bad they'll replace it. They'll test the rectifiers and regulator circuit and replace anything bad on it. They'll put it back together and load test it.

--scott

this is good

seems to be that these kinds of shops are fewer and farther between the nature of the throw-away manuf/engineering designs of most things now

This is absolutely true, this is why we need to support those few shops that are still operating and keep them in business!

I'll put in a good word for my local shop, Dixie Electric in Hampton, VA. They have also rebuilt wiper motors, fan motors, and once a servomotor from a plotter...

--scott

They rebuild most alternators. Throwing it away is throwing away a

I wouldn't patronize anything that had the word Dixie in it.

Is it from a circa 70's vintage Calcomp X-Y Plotter?

Graves Auto Electric (the shop less than one mile West of me) and Neely's Auto Electric and Weeks Auto Electric, over here.

It was a 1970s Tektronix plotter. Better software support than the Calcomp, I thought.

--scott

There was a great rebuild shop?old fashioned, dirty floor, plywood sales counter. They folded shop 1 or 2 years ago. The problem is that everyone went to McParts and bought their crappy rebuilds. Pretty soon there's not much business marching in the door.

Assuming you are using a decent ohmmeter, those numbers seem rather high to me. My + reads zero ohms and my - varies depending on what I measure between about 0 to 1 ohm. I don't think your numbers can be correct. V=IR. Plugging your amp and ohm numbers in you'd have V=34x1.5 => V drop of 51 volts thru the + batter cable, which isn't even possible for a 12 volt system. IF the alternator was keeping teh battery charged before it bit the dust I'd be inclined to think you are getting bad alternators.

Yeah, I decided to go back and measure voltage drops instead of ohms:

- Charge current: 60-55A (decreased this much during my measurements)

- (-) battery term to chassis: 0.01v

- alternator frame to (-) battery terminal: 0.07v

- (+) alternator to (+) battery term: 0.3v

So all seems OK now.

You also have remanufactured parts and rebuilt parts. There is a big difference between the two