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alternator diagram questions

March 01, 2021, 09:16:07 pm

good evening everyone,
I received my alternator in the mail today and I'm not sure about the meaning of the numbers in the drawing.
I'm especially interested in the torque value of the nut for the pulley that i have to remove from the old alternator and install on the new one , but there are other numbers on the drawing that i don't know what they signify. It states tighten mounting hardware to 50-55 ft-lb torque but nothing about the nut for the pulley.

thanks for the help
frank

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Re: alternator diagram questions

Reply #1 – March 01, 2021, 09:23:39 pm

It appears you tighten pully nut to 90 degrees after pully fully seated. I could be wrong though.

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Re: alternator diagram questions

Reply #2 – March 01, 2021, 11:19:49 pm

Frank,

I can't help you with the mysterious diagrams.  You'd think they could write the instructions in plain English.

I replaced my alternator a few months back.  I used the technique shown in the video below to remove the pulley from the old alternator, and to install the same pulley on the new alternator.  Only thing I did different was I wore a cotton glove to hold the pulley.

It worked great for me!  The retaining nut spun right off, and went back on just as easy.  I must admit I did not pay any attention to the "torque" value used to tighten the nut, but just ran it down with my air impact wrench until I couldn't hold the pulley any longer with my gloved hand.  It seems to be plenty tight, and I doubt it is gonna fall off.

https://www.youtube.com/watch?v=pbDWKg8kpQU

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Re: alternator diagram questions

Reply #3 – March 02, 2021, 09:57:51 am

Don't want to throw a wrench in your job but if you can get one install a new alternator pulley,old one may be worn.

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Re: alternator diagram questions

Reply #4 – March 02, 2021, 11:16:55 am

I suspect that's a drawing for people who rebuild these.  Just dimensions and tolerances for some of the interfaces that a rebuilder should check to make sure it still meets OEM requirements.  It's a little strange to have the torque on this kind of drawing.

50-55 ft-lbs. is around the normal torque for that size bolt (for a grade 5 bolt; which is the most common) with lubricated threads.

As far as the pully nut, look for that torque somewhere else in the documentation.  If nothing is available, I would just torque to your best judgement.  Usually the spinning always makes it tighter, so it might have reverse threads. 

You could also look up the torque for that size/pitch thread.  Here's a torque chart that I often use:
http://www.fastenal.com/content/merch_rules/images/fcom/content-library/Torque-Tension%20Reference%20Guide.pdf

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Re: alternator diagram questions

Reply #5 – March 02, 2021, 10:36:48 pm

I'm the same as Chuck, I just use an impact gun.

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