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Alternator Pulley Squeal


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I was just curious if there's a simple fix to an alternator squeal? With my belt off, I can simply turn the alternator by hand and get it to squeal. Never dealt with pulley replacement, and looking at the alternator specifically, don't know if it's more in-depth than say the power steering pump pulley. 

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I was just curious if there's a simple fix to an alternator squeal? With my belt off, I can simply turn the alternator by hand and get it to squeal. Never dealt with pulley replacement, and looking at the alternator specifically, don't know if it's more in-depth than say the power steering pump pulley. 

I’ve had the same problem with no real answer. My alternator would squeak when turned by hand. I tightened my belt more and it stopped the squeak temporarily, but it’s begun to act up again. Other then returning the alternator, maybe you can try and replace the bearing in the back? I don’t know much that’s involved with that, but my old man does, so I’ll try to figure that out.


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5 minutes ago, Dammerung said:


I’ve had the same problem with no real answer. My alternator would squeak when turned by hand. I tightened my belt more and it stopped the squeak temporarily, but it’s begun to act up again. Other then returning the alternator, maybe you can try and replace the bearing in the back? I don’t know much that’s involved with that, but my old man does, so I’ll try to figure that out.


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Yeah, any help would be great. All though I believe from what I've found thus far, I think replacing the rear bearing is rather difficult? Not entirely sure, hence this post. Hoping to generate some traffic to see if there 

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Drop a new alt in if can easily done for around 80. Or just put some machine oil on bearings and run it till she blows. Tighten the belt but to much tension can cause bearings to have additional load and can fail prematurely. Ensure quality of serpentine belt as well. And save old belt for backup. 

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Drop a new alt in if can easily done for around 80. Or just put some machine oil on bearings and run it till she blows. Tighten the belt but to much tension can cause bearings to have additional load and can fail prematurely. Ensure quality of serpentine belt as well. And save old belt for backup. 

The thing is, I just bought this alternator two months ago off of RA.


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I would contact Rock Auto about any warranty it might have.  If it hasn’t been submerged, two months is a pretty short life expectancy for a bearing, even if overloaded due to excessive belt tension

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Horror stories? :confused:

 

 

I perfer the remans as they are cheap and carrier a lifetime or year warranty, which is great for someone hard on equipment with the riggers of being in a kinds of harsh elements. Not to mention availability typically good for them fellas like me and want my part now when I'm There to get it. 

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Horror stories? :confused:
 
 
I perfer the remans as they are cheap and carrier a lifetime or year warranty, which is great for someone hard on equipment with the riggers of being in a kinds of harsh elements. Not to mention availability typically good for them fellas like me and want my part now when I'm There to get it. 

I’ve heard of alternators getting bushings instead of bearings as well as them getting fried or being DOA, though DOA can happen to anything.


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1 minute ago, silvertwinkiehobo said:

1/2" downward deflection, and should be 1/4-1/2" deflection

No offense, but this is meaningless.

 

When tightening a belt you have three options:

  1. The manufacturer installed a tensioning pulley to keep the belt in spec and life is golden
  2. You tighten it by cranking on a bolt and listen to your gut for when its "good enough"
  3. Buy a belt tension gauge as listed above. 
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Not meaningless to me. Unless a belt system has a spring-loaded tensioner, you have to use the older method, which is easier with a gauge, but if you don't have one, this method (taught to me by a former boss) does work well. It's how I instructed Maveric to tension his, and no problems so far. Just because it doesn't mean anything to you, does not mean it doesn't work.

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12 minutes ago, silvertwinkiehobo said:

Not meaningless to me.

Fair enough here. But it is meaningless to anyone else. Including Maveric. There is a lot of tolerance on what will work for the truck. Hence my statement about using your gut feeling to get the correct tension. 

 

Please elaborate on your method. How do you measure your deflection? How much pressure are you using to create your deflection? What type of belt material, thickness, age, etc applies here? Without specific values, tools, and procedures it is completely worthless. Might as well say "just go until its tight" as that means the same thing.

 

Unless you can give me answers to the above questions (good scientific answers not My Uncle BillyJoeBob says... type answers) then I stand by my statement of meaningless.

 

Lets make an analogy. If you are tuning an old fashioned small engine carb you go by sound. Will everyone tune it to exactly the same sound? Nope. Will telling someone the sound you go for mean anything to them even though it means something to you? Not a chance. Does that mean no-one but you can tune a carb so that the engine runs fine? Well of course not. So the moral is that your explanation of the sound doesn't mean anything, and in fact won't matter to anyone else who is tuning their carbs. The tolerance values built into the product allow for everyone to find their own working pitch. Same thing applies here with belt tension. Either get a tool that will allow us to talk about comparable values, or realize that what you are stating is not useful, nor pertinent. 

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I have owned Several XJ’s and an MJ with the 4.0, and all of them need hellishly high belt tension to avoid squealing.
 

My approach is to Tighten the belt “very tight” based on previous experience, and then drive the vehicle from a cold start using the A/C to put the max load on the belt.

 

Invariably, my tension is inadequate, and the belt squeals.  So, I tighten it a bit more and try again.  Sometimes I have to do this 2 or 3 times before I get the tension high enough.

 

The point of all this is that even with a tension gauge, it’s best to do an “approach to zero squeal” to get optimum belt tension.

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Coming at the problem from another angle-

 

A squealing belt can indicate a loose belt, as everyone has commented on.

 

It can also indicate a problem in the battery/charging system, other than the alternator.  A battery that won't hold a charge due to age or damage may have just enough juice to start the vehicle, but then be mostly depleted and the alternator is practically being full fielded by the voltage regulator in an effort to recharge the battery.  A full system inspection might be a good idea: check the battery, battery cable connections, battery cables themselves (cut or broken insulation, internal corrosion), connections at the starter and block, & alternator charge circuit wire.  Cruiser's Tips cover all of these I think and are a great guide.

 

Also, it's good practice to turn off all unnecessary accessories (high amp stereo, heat/AC fan, etc) when shutting down the vehicle, and leaving them off as the vehicle is started/warmed up.  This removes as much load from the battery/alternator as possible.  Turning off the AC, and Defroster (which also engages the AC comp) is also a good idea when shutting down.  That way the AC compressor isn't loading the belt immediately after start up, when the alternator is (probably) trying to recharge a battery that just had a big discharge to start the vehicle, as well as possibly being discharged from sitting for a while.

 

For those that don't know, an alternator that is working hard to recharge is also harder to turn, putting a higher load on the belt.

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