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Posted by: Elliot Cannon Oct 1 2016, 06:04 PM

After the lengthy thread about alternators, I decided I should look into why mine is rattling so badly. This is the second bracket that has broken in less than a year. I was thinking of welding it back together and adding a doubler in the form of a washer or just fabricating a whole new one out of thicker steel. Any ideas why it might have broken in the first place? Is it possible I tightened the belt too tight? Is it possible it is vibrating so much it fatigued the metal?


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Posted by: r_towle Oct 1 2016, 06:06 PM

40 year old steel?

Posted by: tomeric914 Oct 1 2016, 06:08 PM

Surprisingly, I believe they are still available new from the dealer.

Posted by: Elliot Cannon Oct 1 2016, 06:17 PM

Hell, I'm 70 and I know how I feel after lengthy vibration.

Posted by: Elliot Cannon Oct 1 2016, 08:34 PM

Like most of my welding repairs, this one is also ugly but serviceable. I welded a washer to act as a "doubler". I got it installed, adjusted belt tension and will put a few miles on it tomorrow. Maybe I'll order a new one. Like new 40 year old steel.


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Posted by: porschetub Oct 1 2016, 11:04 PM

Hah all good ,that will hold on no problems seen worse welding.

Posted by: Elliot Cannon Oct 2 2016, 10:25 AM

So, you've seen some of my other stuff then?

Posted by: McMark Oct 2 2016, 11:59 AM

The lower bolt is in place and tight?
All the fan blades are intact?
Alternator pulley out of round / bent?

Maybe you need to get your belt balanced.

Posted by: 76-914 Oct 2 2016, 12:54 PM

Couldn't help but notice that the hole was oval. What caused that? Was it loose once?My rule of thumb minimum; the distance between the edge of the bolt hole and the edge of the metal should equal the drilled hole diameter. You've basically corrected that with the washer and the welds resulted in nice filets which will add strength.

Posted by: Elliot Cannon Oct 2 2016, 03:20 PM

I have an idea that I'll be looking for a new alternator in the future. I have noticed since the repair that the alternator is making a pretty loud whining noise. Maybe a bearing issue. Anyway, if I'm going to install a seat heater in the car, I might need more of them amp things to work with. Till then it's producing 13.8 volts at low rpm. I took my belt into NAPA and they balanced it on their dynamic belt balancing and tension setting machine. You should get one of those for your shop.

Posted by: 7TPorsh Oct 2 2016, 08:22 PM

My alternator started whining before it went haywire. Friend told me when the diodes start failing you will start hearing things. Taking it out and man-handling it probably started the unit on the downhill path. Get a Bosch from Pelican while they are in stock!

Posted by: BillC Oct 3 2016, 07:36 AM

The hole was actually made like that, to allow for adjustment. When I cleaned and painted the sheet metal on my engine last winter, my bracket had the same slot.

Posted by: bdstone914 Oct 3 2016, 08:14 AM

I can get ine of my spare alternators rebuilt at a local shop. They charge me $75. I need 25 for the core. Commercial rebuilds are crap and hard to find.