Floppy Alternator Belt - The 1947 - Present Chevrolet & GMC Truck Message Board Network

wxman1 · 08-17-2004, 11:46 AM

Recently changed some of the engine front end components back to
stock. (Alternator brackets, crank pulley, short water pump, back to
stock power steering pump, etc)

Well...I have to move the alternator all the way out to the end of the
upper hold down bracket and its still not tight enough. The upper
hold down bracket look stock compared to whats on some trucks that I know
are bone stock.

So I wonder if some of you guys with 69 C10s with 350/TH350
would post the stock numbers of the alternator belts you're
using if you know them? Maybe I've got an alternator belt that is too long?

Jim
Mt Juliet

toddtheodd · 08-17-2004, 11:52 AM

If you've gone back to stock, the parts store should be able to give you the right part based on your stock specifications. You really only run into problems at the parts counter when you've changed to non-stock specifications.
Todd

69 Short Fleet · 08-17-2004, 11:54 AM

You might want to take the belt off and bring it to a auto parts store and try 1/2" or 1" shorter belt. I'd start with 1/2" shorter and go from there.All the "V belts" I've seen available come in 1/2" incriments. Doug

**raggedjim** · 08-17-2004, 01:30 PM

I agree with Doug, most belt have a number stamped on them and that number is coded to the overall length. Get the number off of your belt and take it to a parts store. Most of them can get you incrementally shorter belts until you find what you want. (I went through this same problem with my blazer...)

Rg

greasemonkey · 08-17-2004, 05:05 PM

Put the alternator in the position you want it in, run a piece of string around all the pulleys and measure how long the string is. That's the length belt you will need.

Tx Firefighter · 08-17-2004, 05:51 PM

The belt will have a 5 digit number.

The first two numbers are the "V" width. Whatever you have, keep the same number.

The last three numbers are the length of the belt in half inch increments.

Example, say you have a 15545 belt. The 15 is the width. The 545 means 54.5 inches long. If you needed it 1/2 shorter, you'd ask for a 15540. An inch shorter would be a 15535, and so on.....

1-PU70 · 08-17-2004, 06:11 PM

There are two top brackets a short and a long. Or my truck came with the wrong bracket. The altinater would hit the valve cover when you went to change the belt. And when you did get the belt on then there was no more adjustment. I found a longer bracket with more adjustment

wxman1 · 08-18-2004, 02:07 AM

Well...I went in to the parts store and got a half inch shorter belt.
Thanks for the explanation on belt dimension coding in the number!
But...when I got the shorter belt...now I have no adjustment. I think
the previous poster is correct...I need a longer upper bracket. I didn't
even know there were 2 different length brackets. Thanks all!

Jim
Mt Juliet

08-17-2004, 11:46 AM	#1
wxman1 Senior Member Join Date: May 2002 Location: mt juliet, tennessee, usa Posts: 237	Floppy Alternator Belt Recently changed some of the engine front end components back to stock. (Alternator brackets, crank pulley, short water pump, back to stock power steering pump, etc) Well...I have to move the alternator all the way out to the end of the upper hold down bracket and its still not tight enough. The upper hold down bracket look stock compared to whats on some trucks that I know are bone stock. So I wonder if some of you guys with 69 C10s with 350/TH350 would post the stock numbers of the alternator belts you're using if you know them? Maybe I've got an alternator belt that is too long? Jim Mt Juliet

08-17-2004, 01:30 PM	#4
raggedjim Senior Member Join Date: Jun 2002 Location: Murray, Kentucky Posts: 3,477	I agree with Doug, most belt have a number stamped on them and that number is coded to the overall length. Get the number off of your belt and take it to a parts store. Most of them can get you incrementally shorter belts until you find what you want. (I went through this same problem with my blazer...) Rg __________________ Roger '68 Short step - https://67-72chevytrucks.com/vboard/...d.php?t=849675 '69 ('70?) 2wd Blazer '70 GMC Jimmy 2wd '73 Firebird - https://67-72chevytrucks.com/vboard/...d.php?t=853203

08-17-2004, 05:05 PM	#5
greasemonkey Registered User Join Date: Dec 2001 Location: Pace, FL Posts: 2,155	Put the alternator in the position you want it in, run a piece of string around all the pulleys and measure how long the string is. That's the length belt you will need. __________________ 1942 Master Deluxe 1969 C/10 1985 Blazer CUCV 1987 Jimmy 2004 Tahoe 2005 Silverado 1500 2005 Silverado 3500

08-17-2004, 05:51 PM	#6
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	The belt will have a 5 digit number. The first two numbers are the "V" width. Whatever you have, keep the same number. The last three numbers are the length of the belt in half inch increments. Example, say you have a 15545 belt. The 15 is the width. The 545 means 54.5 inches long. If you needed it 1/2 shorter, you'd ask for a 15540. An inch shorter would be a 15535, and so on..... __________________ I'm on the Instagram- @Gearhead_Kevin Last edited by Tx Firefighter; 08-17-2004 at 05:54 PM.

08-17-2004, 06:11 PM	#7
1-PU70 Registered User Join Date: Apr 2000 Location: Bradenton, FL Posts: 1,036	There are two top brackets a short and a long. Or my truck came with the wrong bracket. The altinater would hit the valve cover when you went to change the belt. And when you did get the belt on then there was no more adjustment. I found a longer bracket with more adjustment __________________ 1970 CST/10 402,700R4,3:73 posi,AC,PS,PB,TLT,PW,Buckets with heaters

08-17-2004, 11:52 AM	#2
toddtheodd The oddest Todd around Join Date: May 2004 Location: Miami, Florida Posts: 1,418	If you've gone back to stock, the parts store should be able to give you the right part based on your stock specifications. You really only run into problems at the parts counter when you've changed to non-stock specifications. Todd

08-17-2004, 11:54 AM	#3
69 Short Fleet Registered User Join Date: Nov 2002 Location: Kelowna B.C. Canada Posts: 1,086	You might want to take the belt off and bring it to a auto parts store and try 1/2" or 1" shorter belt. I'd start with 1/2" shorter and go from there.All the "V belts" I've seen available come in 1/2" incriments. Doug

08-18-2004, 02:07 AM	#8
wxman1 Senior Member Join Date: May 2002 Location: mt juliet, tennessee, usa Posts: 237	Well...I went in to the parts store and got a half inch shorter belt. Thanks for the explanation on belt dimension coding in the number! But...when I got the shorter belt...now I have no adjustment. I think the previous poster is correct...I need a longer upper bracket. I didn't even know there were 2 different length brackets. Thanks all! Jim Mt Juliet



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