Prestolite Alternator noise

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jbreen - 27 Jul 2007 13:32 GMT

63' Cruiser-50K original-289-AT.........Was out cruisin the other
night in this car . Got it up to 65 mph and I guess I heard the
alternator bearing start to whine, the amp gage start to flicker
(nothing new to this MOPAR unit)...then the noise abruptly stopped and
the gage needle jumped to negative (~10 amps).........I installed a
true NOS Prestolite unit and immediately it started to squeak some on
startup.....continued for 2-3 short drives , then abated. Now upon
start-up, and when under electrical load, it makes that squeaky/
scratchy noise..only when charging. I have had this before in other
Prestos & GM's too. Should I pop in a new bearing ? Are they over
the counter items ?

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RBK. - 27 Jul 2007 13:48 GMT

Tighten the belt and see if it goes away.

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PACKERBACKER - 27 Jul 2007 19:03 GMT

Almost all of the alternators that are normally used on 60's to late 80's
GM, Ford and Chrysler vehicles use the same front bearing and the same
rear bearings. I do not know if the Prestolite bearings will be the same,
but it would not surprise me! If they are please post it.

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keith_kichefski@wed.dresser.com - 27 Jul 2007 23:55 GMT

The Prestolite alternators eventually all squeak. It is not the front
ball bearing, but rather the needle bearing at the rear.
Take a sharp pin punch and poke a hole in the sheet metal bearing
cover. A drop or two of oil, or chassis grease will fix it. The new
bearing has the end cover attached, so no permanent harm. The rotor
is the inner bearing surface, so it is best not to let it run dry for
too long. A circle of tape applied to the back (on a clean surface),
keeps the dirt out. The bearings are common items, at a bearing
supply house. Some of the replacement rear bearings, have a slightly
elongated rear cover, to hold a little extra grease.

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