My original alternator started to squeel whenever I turned on my headlights or braked and came to a stop. So I figured it went bad, but when I took it off it turned fine, but I had already ordered a 100 amp Summit alt. so I went ahead and put it on. Now it seems to be almost worse, why is this, I do have an underdrive crank pulley which could cause it to turn slower but still it is a 100 amp alt. Any ideas.

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'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
FLOWMASTER
EDELBROCK 600CFM CARB.
KN AIRFILTER
UNDERDRIVE PULLEY
ACCEL HEI DISTRIBUTOR
2:73 GEARS

 

Usually when the bearings are bad they squeel.This means its on its way out.
If the new Alt. squeels,return it,it's defective.
Don

 

check the alignment of the pulleys. you ought to be able to find someone with an alternator you could swap on to see if it squeels.

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ICON Motorsports

1st & 3rd

 

Definately check the alignment of the pulleys as stated above and also try loosening or tightening the belt. If I remember correctly the 86 still had the old "belt tensioner system" ie, loosen the bolts and reef on the alt. with a crow bar. My 85 is like that and the belt that goes to alt. has to be super tight not to squeal.

 

406,

Good memory. 1986 was another model year that had the mixed belt system - a five-ribbed poly 'V' for the alternator and standard 37° V belts for all the other drives.

Since the car has underdrive sheaves, and they do wear quickly if they are aluminum, I would suspect belt slippage under load. An alternator with a bad bearing would make noise all the time, not only when under load. Since yours is only noisy under load, the belt is probably slipping. It might not be slipping at the alternator, however. It could be slippage at the crank sheave. I'm guessing your original alternator was probably O.K. too.

March and other aluminum sheaves are notorious for short lives in 'V' belt applications, and I would suspect the same in the poly V applications. Of course, they aren't likely to tell you that in their advertisements.

Incidently, you did install a new belt with the alternator, didn't you?

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Later,
Vader
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"I'm'a do Things My Way - It's My way or the Highway."
Adobe Acrobat Reader

 

Maybe this is the problem, I recently replaced the alternator belt, but Trak Auto only had 4 groove belts, could this be the whole problem.

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'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
FLOWMASTER
EDELBROCK 600CFM CARB.
KN AIRFILTER
UNDERDRIVE PULLEY
ACCEL HEI DISTRIBUTOR
2:73 GEARS

 

Mark,

I believe you might just have answered you entire problem.

------------------
Later,
Vader
------------------
"I'm'a do Things My Way - It's My way or the Highway."
Adobe Acrobat Reader

 

OK, I installed a 5 groove belt today and still squeeling. Any ideas, the belt has about a 1/4" play in it. The squeeling doesn't seem to be as bad now when I go to brake, but at night when I have my lights on it is still noisy. I guess tomorrow I will try to get the belt as tight as possible. Any other ideas for the time being.

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'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
FLOWMASTER
EDELBROCK 600CFM CARB.
KN AIRFILTER
UNDERDRIVE PULLEY
ACCEL HEI DISTRIBUTOR
2:73 GEARS

 

Mark,

My alternator did the same thing after I had it loose recently - squeal under load. It was the belt tension - it had to be super tight before it would stop squealing. No play to speak of. This probably isn't good for the bearings in the alternator, but it's a lifetime warranty unit so wtf. Maybe if the alternator sheave was a larger diameter and had more surface contact area this wouldn't be a problem - but the small diameter is probably why they used the multi-ribbed poly v-belt design...

 

fix your short
and it will stop
squeeling.

 

The belt is totally tight now, no play. It's not as bad, but still if I turn on my heat or lights it squeels a little.

------------------
'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
FLOWMASTER
EDELBROCK 600CFM CARB.
KN AIRFILTER
UNDERDRIVE PULLEY
ACCEL HEI DISTRIBUTOR
2:73 GEARS

 

There's a stick spray you can get at any autoparts store which is made especially for slipping belts. It also "conditions" your belts whatever that means. I had the same problem years ago and that stuff works like a charm.

[This message has been edited by Cool Runner (edited March 19, 2001).]

 

Cool, Till it gets wet or dusty.


My alternator sounds like a quite supercharger, I sorta Dig it


But back to the topic, ODB brings up a good point.



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60 Ranchero - Project ( Money Hole )
85 Sport Coupe LG4 - Daily Driver

Just another Hot Rod kid, or thats what they all tell me.
Livin' the Stereotype

 

Sorry for the stupid question, but I am an idiot when it comes to working on cars, ODB where or what is the short you are talking about.

 

I don't know. It's either in your car or in your battery. If you have replaced the battery and it's still squealing then it's in the car somewhere.
start disconnecting fusable links until it stops.

 

if it doesn't kill the battery from just sitting turned off, then I'd think the draw is only when the ignition is turned on. Could be about anything, even your starter. You have to use a process of elimination to find a short if that's what it is.