Confusing alternator bracket
Thread Starter
Racer
Joined: Oct 2008
Posts: 276
Likes: 5
From: Aptos, CA
Confusing alternator bracket
I am having the toughest time adjusting my alternator on my '69.
Sorry it's not the best picture.
I have the curved upper bracket and a two-piece hinged lower bracket.
The lower bracket anchors to the first two header bolts. The hinged portion can adjust forward and backward along the length of the bolt holes drilled in the anchored portion.
Is this a factory set up for a '69?
It seems incredibly difficult to get "just right" and I have a feeling the lower bracket was bent by the previous owner.
I guess I would like a more trouble free alternator bracket, or be able to figure out how to make this one not be such a PITA.
Know what I mean?
Sorry it's not the best picture.
I have the curved upper bracket and a two-piece hinged lower bracket.
The lower bracket anchors to the first two header bolts. The hinged portion can adjust forward and backward along the length of the bolt holes drilled in the anchored portion.
Is this a factory set up for a '69?
It seems incredibly difficult to get "just right" and I have a feeling the lower bracket was bent by the previous owner.
I guess I would like a more trouble free alternator bracket, or be able to figure out how to make this one not be such a PITA.
Know what I mean?
Burning Brakes
Joined: Aug 2005
Posts: 1,164
Likes: 1
From: Europe, France
I don't know what the factory setup was in 69, but on my 73 the upper bracket is just like yours and attached to the waterpump upper bolt.
But on my car, the lower bracket is made of cast iron, so it cannot be bent. If yours is made of steel, it's probably not the original one.
Maybe the bracket was broken and the previous owner made one instead of buying a new part...
Here's a picture showing the lower bracket ( even if it's a CS130 alternator, it is the GM original U-bracket ) :
But on my car, the lower bracket is made of cast iron, so it cannot be bent. If yours is made of steel, it's probably not the original one.
Maybe the bracket was broken and the previous owner made one instead of buying a new part...
Here's a picture showing the lower bracket ( even if it's a CS130 alternator, it is the GM original U-bracket ) :
Last edited by 73StreetRace; Apr 24, 2010 at 03:43 AM.
Melting Slicks
Joined: Sep 2004
Posts: 2,655
Likes: 19
68 and 69s had the alternator mounted off a boss on the exhaust manifold. With the headers someone added a generic aftermarket mount. They bend easily but genersally work.
http://www.summitracing.com/parts/SUM-G4051/
If your drivers side head has the 2 holes in the top corners, you can use an iron bracket like 73 shows. Or there are other aftermarket mounts for short water pump
The upper adjusting arm you've got should be fine.
http://www.summitracing.com/parts/SUM-G4051/
If your drivers side head has the 2 holes in the top corners, you can use an iron bracket like 73 shows. Or there are other aftermarket mounts for short water pump
The upper adjusting arm you've got should be fine.
Thread Starter
Racer
Joined: Oct 2008
Posts: 276
Likes: 5
From: Aptos, CA
Thanks guys.
I might just look in to getting that iron bracket.
I definitely think the portion of the steel bracket I have that grabs the alternator and allows it to pivot is bent.
When I connect it, and bring the alternator up into position on the upper bracket it doesn't line up meaning the casing of the alternator is not parallel to the flat edge of the upper bracket.
I might just look in to getting that iron bracket.
I definitely think the portion of the steel bracket I have that grabs the alternator and allows it to pivot is bent.
When I connect it, and bring the alternator up into position on the upper bracket it doesn't line up meaning the casing of the alternator is not parallel to the flat edge of the upper bracket.
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Le Mans Master
Joined: Oct 2000
Posts: 8,897
Likes: 1,357
From: Santa Ana CA
My header bracket (similar to yours) is a POS (probably like all the others). It is made of 3/16" steel that was "stamped" to make the bends. Unforetunately, when the engine torques and pulls on the belt, it straighens out these bends like an accordion. I've gone to great lengths to solve this problem and these solutions work, but there is still some flex.
Thread Starter
Racer
Joined: Oct 2008
Posts: 276
Likes: 5
From: Aptos, CA
Thanks for the suggestions and help guys.
I noticed this problem because I removed my belts to inspect my failing water pump which I am replacing today. I'll check to see if my passenger side head has the needed holes.
That iron bracket seems like a much more solid solution for stability and alignment than what I currently have.
Another quick question. My new water pump shaft doesn't turn as freely as the old one. Is this normal, are the seals just tight or should I be concerned?
-Brad
I noticed this problem because I removed my belts to inspect my failing water pump which I am replacing today. I'll check to see if my passenger side head has the needed holes.
That iron bracket seems like a much more solid solution for stability and alignment than what I currently have.
Another quick question. My new water pump shaft doesn't turn as freely as the old one. Is this normal, are the seals just tight or should I be concerned?
-Brad
Pro
Joined: Jul 2005
Posts: 517
Likes: 7
From: Peoria IL
It's normal for new water pump seals to be a little tight.
C3's, at least mid- to late- 70's Corvettes for certain, did not use the standard "short" water pump that 60's SBC's did. I found this out the hard way.
Corvette water pumps are a little longer overall (pulley flange to block surface) and have room for a deeper pulley than the generic "short" pump. I machined some spacers to put the pulley where it needed to be but then found that I needed more clearance for the pulley (it then rubbed the pump) than I could get by just grinding a few spots on the water pump.
GM Performance, Edelbrock, and Weiand make aluminum versions of the correct pump for C3's. Generic "short" water pumps just won't work.
I ended up buying the GM pump and it worked fine with my stock '76 pulleys and iron alternator bracket. My upper bracket looks just like yours.
C3's, at least mid- to late- 70's Corvettes for certain, did not use the standard "short" water pump that 60's SBC's did. I found this out the hard way.
Corvette water pumps are a little longer overall (pulley flange to block surface) and have room for a deeper pulley than the generic "short" pump. I machined some spacers to put the pulley where it needed to be but then found that I needed more clearance for the pulley (it then rubbed the pump) than I could get by just grinding a few spots on the water pump.
GM Performance, Edelbrock, and Weiand make aluminum versions of the correct pump for C3's. Generic "short" water pumps just won't work.
I ended up buying the GM pump and it worked fine with my stock '76 pulleys and iron alternator bracket. My upper bracket looks just like yours.
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
Factory cast iron bracket holds my belts and tension to 7500RPM upshifts on my 72 LT-1 GM did this part RIGHT. This is what you should be searching for to eliminate problems on your Vette.
