Factory AC alternator bracket - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Dieselholic92 · 08-28-2016, 12:02 PM

Guys with factory AC pickups. Do you have issues with the upper alternator bracket being flimsy and vibrating a lot? Mine on my 72 GMC wobbles/vibrates really bad at any engine speed over idle. Going down the road you can hear it vibrating. It's already cracked once but didn't break. The crack has been welded, and everything is as tight as it can be. Maybe it's the alternator? Is there a solution?
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Dieselholic92 · 08-31-2016, 03:35 PM

Anybody have any experience with this?
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**FirstOwner69** · 08-31-2016, 10:41 PM

I don't think I've seen anyone else post anything like that. Try posting a picture of what you have. Is it safe to assume assume the A/C compressor is on the passenger side and the alternator is on the driver side? What year and engine?

**DeadheadNM** · 09-01-2016, 12:11 AM

I had an rpm dependent vibration in my non-AC gmc related to an alternator bracket, but it was the lower of the two brackets. The bracket lacked the bronze (?) bushing at the rear hole for the longer bolt.

RedRoad · 09-01-2016, 04:11 AM

the original 1972 one year only brackets are the longest of the bunch, they do tend to flop around a bit and crack like you mentioned . The common fix it to get two, stack them and install with longer bolts to firm the whole thing up.

I believe the 72 vette uses the same bracket.

Dieselholic92 · 09-02-2016, 10:18 AM

Thanks for the replies guys. I'm in the black hills for the weekend, so I'll post some pictures when I get back. That's correct, the AC compressor is on the passenger side and the alternator is on the drivers side.
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Dieselholic92 · 09-05-2016, 08:02 PM

Here's some pictures. You can see where the alternator bracket cracked and was welded back together.

It chatters quite a bit, especially when going down the road. I'm not sure if it is the alternator or the bracket.

08-28-2016, 12:02 PM	#1
Dieselholic92 Registered User Join Date: Feb 2012 Location: Lynd, Minnesota Posts: 201	Factory AC alternator bracket Guys with factory AC pickups. Do you have issues with the upper alternator bracket being flimsy and vibrating a lot? Mine on my 72 GMC wobbles/vibrates really bad at any engine speed over idle. Going down the road you can hear it vibrating. It's already cracked once but didn't break. The crack has been welded, and everything is as tight as it can be. Maybe it's the alternator? Is there a solution? Posted via Mobile Device __________________ Semi professional heavy equipment operator Amateur mechanic

08-31-2016, 03:35 PM	#2
Dieselholic92 Registered User Join Date: Feb 2012 Location: Lynd, Minnesota Posts: 201	Re: Factory AC alternator bracket Anybody have any experience with this? Posted via Mobile Device __________________ Semi professional heavy equipment operator Amateur mechanic

08-31-2016, 10:41 PM	#3
FirstOwner69 Senior Member Join Date: May 2010 Location: Wisconsin & Arizona Posts: 4,844	Re: Factory AC alternator bracket I don't think I've seen anyone else post anything like that. Try posting a picture of what you have. Is it safe to assume assume the A/C compressor is on the passenger side and the alternator is on the driver side? What year and engine?

09-01-2016, 12:11 AM	#4
DeadheadNM Carpe manana Join Date: Dec 2010 Location: Eau Claire, WI Posts: 12,357	Re: Factory AC alternator bracket I had an rpm dependent vibration in my non-AC gmc related to an alternator bracket, but it was the lower of the two brackets. The bracket lacked the bronze (?) bushing at the rear hole for the longer bolt. __________________ 1972 K5 CST Highlander Blazer: http://67-72chevytrucks.com/vboard/s...d.php?t=708547 1972 K20 Cheyenne Super: http://67-72chevytrucks.com/vboard/s...d.php?t=528308 Members met: ORANGBLAZ, 2003 silverado, MikeCofield, BB72CHEVKT, Duncan&Son, Sameyrasmea72, THENEWMEXICAN, HotRod C/10, brianthelion02, Sport/Truck, ryanroo, michael bustamante, Dirt's72, Already Gone, WestButteTruck, 57taskforce, Moreyel, painterljp, AASmedic, SoCoC10, Lumaestas, carbuff382, Chevyland

09-01-2016, 04:11 AM	#5
RedRoad Registered User Join Date: Jan 2015 Location: Los Angeles California Posts: 927	Re: Factory AC alternator bracket the original 1972 one year only brackets are the longest of the bunch, they do tend to flop around a bit and crack like you mentioned . The common fix it to get two, stack them and install with longer bolts to firm the whole thing up. I believe the 72 vette uses the same bracket.

09-02-2016, 10:18 AM	#6
Dieselholic92 Registered User Join Date: Feb 2012 Location: Lynd, Minnesota Posts: 201	Re: Factory AC alternator bracket Thanks for the replies guys. I'm in the black hills for the weekend, so I'll post some pictures when I get back. That's correct, the AC compressor is on the passenger side and the alternator is on the drivers side. Posted via Mobile Device __________________ Semi professional heavy equipment operator Amateur mechanic

09-05-2016, 08:02 PM	#7
Dieselholic92 Registered User Join Date: Feb 2012 Location: Lynd, Minnesota Posts: 201	Re: Factory AC alternator bracket Here's some pictures. You can see where the alternator bracket cracked and was welded back together. It chatters quite a bit, especially when going down the road. I'm not sure if it is the alternator or the bracket. __________________ Semi professional heavy equipment operator Amateur mechanic

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