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 ?
Prestolite Alternator noise
Jul 27, 2007
3 Replies
Tighten the belt and see if it goes away.
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.
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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