Alternator noise

[1stgen68]

Need help with alternator loud a$$ noise after changing the alternator top bracket to clean off some surface rust. After i took it off and placed it back in its spot all hell broke loose.
Looks like it's not engaging until after about 5 seconds of running and makes the most god aweful screetch. Please tell me what i did wrong with putting it back on or how it needs to be adjusted.
I can't attach .mov files or else i would.

[Mike S]

Are you certain that the belt is not too tight thereby causing the front bearing to make noise?
 You can use a long screwdriver and hold it on a suspected area and listen to the handle....or....safer yet buy one of these Dr. Kildare type of scopes:
https://www.harborfreight.com/search?q=mechanics%20stethoscope

 I own that and swear by it, plus is it s hell of a lot safer to isolate mechanical noise.

Mike

[1stgen68]

I unloosened the bolt holding the alternator on to tighten the belt. Fired it back up and the loud screetch is gone but still squeeking from the belt and shut it back down. Is the belt supposed to be tight or loose?

[1stgen68]

also now the fan blades on the alternator aren't turning at all

[L78racer]

alt. pulley nut loose?

[1stgen68]

I was able to adjust the top alt bracket and stop the crazy screetch but now sounds like the surp belt is loose type of sound. Not sure if it's the alt belt or surp belt. None of this happened until i had a bright idea to remove the top chrome bracket to clean off some surface rust today.

[1stgen68]

also still the alt blades aren't spinning and i think they should be right? To stop the screetch, i loosened the bolt that hold the alt in place and lowered it just a little and then re-tightened it. Fired it up and sounds now like the alt belt or surp belt is loose.

[1stgen68]

i validated that the atl pulley is not loose.

[Mike S]

What year car? It has a serpentine belt? I adjust my belt just enough where if I place a straightedge between the water pump and alternator pulley and press down in the middle of the belt, I should see about a 1/2"-3/4" deflection.

Mike

[WorkinProgress]

If you cannot spin the alternator, then the squeal you hear is the belt trying to turn an armature that is frozen and NOT turning.

Sounds like your alternator is in need of a rebuild.

                                          - Warren

[ko-lek-tor]

Probably the fan is hitting the bottom of the top adjusting bracket, if you ask me? Seen it before.

[1stgen68]

Got help over here and turns out that i didn't have the alt belt tight enough and the dang bracket had to be adjusted just enough to NOT hit the fan blades. This is something that i will never miss next time for sure. Thanks for the help guys!! Sorry to waste your time