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Discussion Starter · #1 ·
I took my '55 Bel Air out this weekend and it started making a strange noise, mostly at low RPMs.

The sounds is not constant but it sounds as if the fan is hitting the radiator periodically. After close examination it's not the fan. The sound is coming from the generator. At first I thought the cooling fan on the pulley was hitting the housing but it's not.

To make sure it was the generator I removed the belt to confirm, and it is definitely the generator.

I oiled it with light motor oil as per the service manual and it did seem to help a little, but it's still making the noise.

I'm thinking I'm going to need to do a re-build but I've never attempted to rebuild one before and I'm a little apprehensive.

How difficult is a generator re-build?

Any ideas what could be making this sound?

Thanks,

Gary
 

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Gary, It's a piece of cake to tear down. I used an impact with a 15/16" with a towel holding the fan (keep the fingers safe) on the end of the generator, just give it little hits of the trigger instead of laying into it. the two rear bolts are 7/16" if my memory serves me right. make sure you mark the housing and both ends so you reassemble it correctly. I had mine apart to fix the brushes last week, it sounds to me that you'll be replacing the bearings.

:anim_25:

Jim
 

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They are not that hard to rebuild ,,,I believe the front and back plates are silver and the body is semi gloss black ,,get the correct repro tags and once rebuilt it will look and work great ,,:anim_25:and :pics-1:
 
G

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I do them all the time, but I am in the business, and have done same for decades. Generators aren't that hard to do, but can be very intimidating for the novice that hasn't done one before.

The most common wear item I have found is the rear busing in the end cover plate. When the bushing wears, it is usually fro the belt pulling the alternator stator (the center windings and shaft), in one direction from belt tension, and oblongs the bushing. This usually does not hurt the shaft end where it fits into the bushing. What it does do is allow the windings on the center shaft to rub against the yokes of the outer windings, making all sorts of strange sounds, from grinding to 'screeching'.

I'd suggest an easy to do first step, remove the generator from the vehicle. Mark the case and end cover so the cover can be installed n the same position. fit the generator so the front end is down, end cover up, remove both bolts (they are LONG ones, they go the entire length of the generator). Pull the end cover off, and take a look at the rear bushing. If it is damaged, the damage should be very evident and easy to see.

The old busing can be a pain to remove in come cases, but not if it is elongated enough to weaken one side of it. New bushing should just tap into place.

From there, the rest of the dis-assembly/re-assembly should be done by someone that knows how to do it right, NOT hard, but, it has to be done correctly. Seek a knowledgeable friend that has done one before, to go farther.

Usually, front bearings don't go bad, nor wear out in those units, but, there is always the exception to the rule.
 

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Discussion Starter · #10 ·
What it does do is allow the windings on the center shaft to rub against the yokes of the outer windings, making all sorts of strange sounds, from grinding to 'screeching'.
Thanks, I've got the screeching sound!

It just started so hopefully the damage won't be too bad.

I plan on tackling this either this weekend or next. Thanks again for your input.

I'm pretty mechanically inclined and I plan on using my iPhone camera to document the disassembly so I don't forget how things go back together.

I can't learn unless I try, right?

Gary
 
G

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If you get stuck with it, there are many here that can, and will help.

You'll be just fine with it, very straight forward operation.
 

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This is just me, but I would convert to an alternator. They are more dependable than the old generator/regulator setup. They also supply more than 25 amps. My 1993 CS130 puts out about 105 amps at idle if needed to . When battery is fully charged will automatically lower it's output.
 
G

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Depends on if his car is dead stock and he wants to keep it that way.

I have converted a few of the older generators to alternator, by machining in a Japanese alternator into the GM generator body, so it looks stock/stealth.
 

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Discussion Starter · #14 ·
Depends on if his car is dead stock and he wants to keep it that way.

I have converted a few of the older generators to alternator, by machining in a Japanese alternator into the GM generator body, so it looks stock/stealth.
Yes, it is and yes I do.
 
G

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So, diis be one uh dem times a gen-a-rater be da' thanggggg!

If you decide to go farther after you get the rear cover off, simple, put the thing upright rear end up, and simply pull up he body. You will see/hear the brushes come off the rotor, and then, the whole body lifts right off. It is pinned, so it goes back together one way only. The locating pin is on the front cover flange where the body connects.

Usually, the front bearing isn't damaged, but, do look closely, they do lose lube.

A note about the correct bearing style to use in the front. Bearings have different "fit" specifications, to identify the looseness built into the bearing. Old specifications used to run C1-C2-C3-C4-C5, etc. 1 being the tightest bearing, 5, the loosest. The loosest allowed for the widest angle in the bearing, 1, least misalignment.

All that hoopla said, we use C3 fit bearings in the front of our generators and alternators. Newer specifications are named different, but have the same looseness in the bearing. If you ever see "EMG" after the bearing, it stands for "Electric Motor Grade", and IS the same as a C3 fit.

Example: 6302-C3 is the exact same bearing as a 6302-EMG, and so on.

Just more FYI.
 
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