[DeTomaso] Alternator shake fixed!

[Dave McManus]

Please provide an update in a few days and then again in a few days.
IndyDave

-----Original Message-----
From: Mike Drew [mailto:MikeLDrew at aol.com] 
Sent: Tuesday, May 16, 2017 10:30 PM
To: De Tomaso Forum
Subject: [DeTomaso] Alternator shake fixed!

Hi guys,

You may remember that months ago (October!) Lori's Pantera ate another alternator. One died in the parking lot at the Fun Rally, I changed it there, a second one broke a few days later on the drive home. Changed it out the next day, and the third one died after about 200 miles. 

Turns out they were being shaken to death as captured in this crappy IPhone video:

https://youtu.be/05CddX-lbew

I couldn't see why it was shaking and wondered if the mount had a broken weld or something. 

The car sat for months while we worked on other things (including several steering racks). With the Fun Rally fast approaching I finally decided to investigate further. 

A peek at the front of the motor revealed that everything was absolutely fine, belts running true and brackets rock-solid. 

https://youtu.be/LFFc5V7nwQg

Crawling under the car, I could easily move the alternator with my hand, or by pinching the belt together. I removed the old alternator, and investigation showed exactly why it's charging was so intermittent. 

https://youtu.be/B-qkBLzhVek

I measured the width between the tangs of the mounting bracket, and the boss on the alternators (old and new) expecting to see a slight difference, but they were exactly two inches. 

Hmm.

I compared the inside diameter of the holes in the bracket and the boss, with the outside diameter of the bolt, and they were a perfect match. 

I installed the new alternator with the bolt finger-tight and it still rocked around quite a bit--worrying. I finally decided to get an extra-long ratchet and torque the hell out of the main mounting bolt. In so doing, I probably slightly deformed the bracket mounting ears so they fit flush against the edges of the alternator mounting boss. 

I'm happy to report it is now absolutely rock-solid. I can't say if prior failures were caused by failing to tighten the bolt enough, but I will say that previously I was using a standard ratchet and tightening as much as I could. The extra length of the longer ratchet this time perhaps allowed me to over-torque the bolt, but apparently that is what was called for. 

In any case, everything is tickety-boo now!  Monterey here we come!

Mike

Sent from my iPad