Alternator pulley nut fell off

BILLFSHR

MEMBER
1990 FORD F-250
5.8L
V8
4WD
AUTOMATIC
100,000 MILES

I just replaced my alternator because the pulley fell off, went for test drive and lost the nut on the pully again, what am I missing? Signed: frustrated lol

Wednesday, November 24th, 2021 AT 11:30 AM

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,755 POSTS

Hi,

Did this pulley come with the new alternator, or did you have to use the old one? Also, how tight did you make the pulley? Also, if you did tighten it to spec and it still came off, you may want to use Loctite on the threads. That should prevent it from coming off.

Also, if you did have to install the old pulley, take a look through this link, and let me know if this is what was done.

https://www.2carpros.com/articles/remove-reinstall-power-steering-pulley

Let me know.

Joe

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Wednesday, November 24th, 2021 AT 10:42 PM

BILLFSHR

MEMBER
9 POSTS

The new alternator came with the pulley installed, but let me start at the beginning, I had a power steering leak, at this time the alternator had been on about 9 months, then I was driving home, and the serpentine belt broke, I made it home okay, ordered a new high-pressure hose for the power steering. And installed it, went to install new serpentine belt and realized the bolt for alternator pulley was gone, it was under warranty, so I got a new alternator (rebuilt) and installed it, and new belt, went for test drive, returned home to see the alternator pulley retaining bolt missing, the pulley was just hanging there. The power steering pump seems fine, it's not seized, could a bad power steering pump even cause the alt pulley bolt to loosen? I checked belt tension when I installed the belt and it was good, I have no clue how this keeps happening.

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Thursday, November 25th, 2021 AT 7:49 AM

JACOBANDNICKOLAS

MECHANIC
109,755 POSTS

Hi,

I don't feel something other could be causing the issue. When the belt is installed, is it riding evenly on the pulley? Also, check the pulley on the alternator to make sure it has the same number of ribs as the belt has.

Considering the same brand remanufactured alternator did the same thing, either get a new bolt and use Loctite on it or if you get a new one under warranty, remove the nut and install Loctite. That should prevent this from happening again. It sounds like they are not tightening the nut enough.

Let me know if that takes care of the issue or if you have other questions.

Take care and I hope you had a nice Thanksgiving.

Joe

I attached a pic below showing the belt routing diagram. Make sure it is correct as well.

Image (Click to make bigger)