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How can a Alternator Rotor Shaft Snap

mitweiler

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Hi,

I need some advice please. I have just replaced my alternator with a rebuilt one with genuine parts (apparently). After 4 days of driving the rotor shaft on the alternator had snapped.

Could somebody please explain how such a thing can happen?

I returned my car back to the mechanics, on a tow truck and he replaced it with another rebuilt one. I was told “The only way that the rotor shaft can snap is due to revving the engine repeatedly while on idle, because it is a powerful high revving engine it can quickly pick up the revs which is why the rotor shaft snapped”. Basically, made me feel like it was my fault. I drive a VY manual, clubsport. Standard engine no modifications at all to the engine.

He believes it’s a common fault with the LS1’s. I believe it’s bullshit what his saying and does not make any sense what his saying.

What you guys think? Anybody had a similar issue.
 

greenacc

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If it was a rebuilt one it could have had a hard life with the previous owner. Does the shaft get replaced during a rebuild?
Could be a manufacturing fault or abuse during the rebuild as well.
 

the_boozer

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I was told “The only way that the rotor shaft can snap is due to revving the engine repeatedly while on idle, because it is a powerful high revving engine it can quickly pick up the revs which is why the rotor shaft snapped
Did you rain blows on the bullshit artist what a load of **** thats the quality of so called new parts these days great isn't it one of the bearings seized is my guess most likely installed the wrong way around. When I was in my early 20's I changed the bearings in a vc alternator and put the rear bearing in the wrong way it only had a dust cap on 1 side the carbon from the brushes got in that alternator seized with in a couple of days.
 
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Immortality

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Cool story, I'd say it's more likely it was a poor rebuild and the idiot is making excuses for his poor work. I'd think the belt would slip before a physical breakage if there was a sudden change in rotor speed. Later model alternators do have a clutched pulley for just this reason.
 

mitweiler

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If it was a rebuilt one it could have had a hard life with the previous owner. Does the shaft get replaced during a rebuild?
Could be a manufacturing fault or abuse during the rebuild as well.

To be honest I have no idea, maybe somebody here can answer that. If it doesn't get replaced then from all the years of vibrations and use it could of weakened the shaft and caused it to snap!
 

mitweiler

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Did you rain blows on the bullshit artist what a load of **** thats the quality of so called new parts these days great isn't it one of the bearings seized is my guess most likely installed the wrong way around. When I was in my early 20's I changed the bearings in a vc alternator and put the rear bearing in the wrong way it only had a dust cap on 1 side the carbon from the brushes got in that alternator seized with in a couple of days.

Hahaha I tried explaining to him what he is saying makes no sense. But he was so sure of it and told me not to come back if the same problem happens as he will not replace it under warranty again.

I told him that's fine, I didn't pay him I paid the other guy (mechanic) across the road. He purchased the alternator off him and had it installed. I only took it to him because my mechanic was not working on Saturday and he told me to drop it in to him and he will look at it as the alternator is from him.

If the issue happens again. I am now currently emailing a few auto electricians asking how a rotor shaft can snap. If nobody says it's from over revving I will print out and take it to my mechanic and say. I purchased and paid for a new alternator from you. I have 6 months warranty from you. Please repair it or give back money. Here is proof what the guy across the road is saying is incorrect in case he gives you a hard time.
 

mitweiler

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Cool story, I'd say it's more likely it was a poor rebuild and the idiot is making excuses for his poor work. I'd think the belt would slip before a physical breakage if there was a sudden change in rotor speed. Later model alternators do have a clutched pulley for just this reason.

Okay that's good to know. He mentioned he put in a later model alternator off a newer V8. So hopefully it has this clutch pulley so I don't get this issue again. I to believe it's a poor rebuild as well. If i wasn't in such a hurry to get my car back on the road I would of shopped around for a genuine brand new alternator which would of saved me this hassle :(.. oh well learn for the next time!
 

Towcar

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I really don't understand why he'd even reco an alternator, a good new one is close to the price of a reco.

Over here I'd be going to the MTA about it, something breaking in 4 days has to be poor workmanship or poor installation.

As far as him telling you not to come back if this one breaks, we also have the consumer protections act in NZ, in Australia there is similar so he hasn't a leg to stand on, and in NZ it would be actually an offence for him to tell you that you have no rights.

Sounds like a dodgy cnut to be honest.
 

mitweiler

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I really don't understand why he'd even reco an alternator, a good new one is close to the price of a reco.

Over here I'd be going to the MTA about it, something breaking in 4 days has to be poor workmanship or poor installation.

As far as him telling you not to come back if this one breaks, we also have the consumer protections act in NZ, in Australia there is similar so he hasn't a leg to stand on, and in NZ it would be actually an offence for him to tell you that you have no rights.

Sounds like a dodgy cnut to be honest.

The alternator guy is dodgy yeah. I called my mechanic early in the morning and asked if he could have it fixed that day as I needed my car. So he went and sourced an alternator from the guy across the road. So maybe not enough time to get or order a brand new one :/ I'm not sure.

I spoke to him about the situation when I took the car back. He apologized for the other guy and said if there are any more issues to bring to him and he will sort it out. He also agreed with me saying the alternator should not have failed and was bullshit what the other guy said.

So speaking to him has reassured me I will be looked after if any happens. So I'm happy now.
 
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