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Confused by Alternator Tensioner Bolts? Some tips

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#1
Alberto

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I had to replace the alternator.  I noticed when unloading the car after the last race that the headlights were dim and a voltage test confirmed the alternator was not working properly.  Can't complain too much as the alternator was original to the car so 22-23 years old and 182k miles.  The tensioner bolts on the alternator confused me a bit and, from what I've noticed in the pits, I'm not the only one.  So I took some pics and wrote them up on a blog post hoping it will help other newbies and others like me.

 

 

Anyone else have any tips to share?

 

 

Link to blog post:

http://blog.miatarac...ernator-on.html

 

Link to a helpful how-to pic on tensioning the belt and tightening the bolts:

alternatortensionbolts.jpg


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#2
Keith Novak

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Loosen the lower bolt it pivots on as well.  Where the tensioner bolt screws in is aluminum.  I've stripped on out when I didn't loosen everything up first.


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#3
LarryKing

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Check the upper alternator bracket from time to time. They have a habit of cracking which results in misalignment of the alt pulley.

 

Also, it's easy to overtighten the belt with the tensioner.


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#4
Jeff Wasilko

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Be sure to loosen the lower bolt. I ended up cracking the tensioner ear that's part of the water pump last season, which means I got to replace the water pump this winter. It was a bitter pill to swallow.



#5
zcoley1954

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anybody know the exact size and length of the top shorter bolt? because I lost mine and don't know which will fit



#6
Alberto

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I don't know exact length but it isn't very long.  Probably 1.5 - 2".  

 

Here is a link to my photo album with more pics of those bolts

https://picasaweb.go...CJWE4rOp_MuBeg#

 

And here is a pic of the bolts:

alternator%2520%25284%2529.JPG


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#7
Bruce Wilson

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We give the tensioner bolt (long) one more slight turn after the lockdown bolt (top short) is tight, just to make sure it's all snug. 

 

So, adjust tension -> tighten lockdown -> snug tensioner -> tighten lower.


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