Alternator Problem

[hoyboy1986]

I got a 89 Grand Wag with a screaming alternator. Well not to sure if it's the alternator but when it's yelling charge drops and the alternator was just recently replaced with a jumk yard pull. The thing is, it only screams when in park, when put into drive, it goes silent and charge goes back to normal. I have been told I need new bushings but before I go out buying parts, I would like to get the opinion of you fine people :D

Any help would be appreciated

(p.s. Any idea what model the alternator could be? If I remember correctly I pulled it from a GM but I was wondering what types of alternators came on that year. Any help would be nice on this too :D )

[andy d]

its not the belts?

[woodybeone]

The reason the squealing stops in drive is probably because the idle drops as the motor is under load. As Andy stated check and tighten the belt. If it's a junkyard find check the pully as it may not be the correct one.

63amp was standard, 78 and 83 were optional I believe.

[hoyboy1986]

All the belts were replaced minus AC belt when the "new" alternator was put on. The pulley is the same exact one from the old alternator, we scavenged the double pulley off the old one and put it on the "new" one.

[Joe Guilbeau]

Which alternator did you pull and from what application?

Details...details...details...

http://207.158.252.111/gw/alt/Alternator_Theory_Draft_10.html

[hoyboy1986]

From the link Joe gave me, I have a 12SI Delco with a double pulley. To be honest, I don't remember what the make of the car was that I pulled it from.

[Joe Guilbeau]

The belt is in need of attention and is probably going, and the torque on the alternator is helping it along.

Do you have all of the various brackets and the housing that goes over the long bolt at the top?

Is the belt shiny on the sides?

When you disconnect the alternator and spin the pulley, is there any play or sound?

Playing around with it tells you a whole lot of things that you would never guess about it.

[hoyboy1986]

The belt was a tad shiny on the sides. I disconnected the alt. and spun the pulley and there was no "play" or sound. About the brackets and housing, I don't think I have all those. If I could see a pic of those, that would pry help me out. If I don't have all of those I would guess that's my problem.