Changing rearends - The 1947 - Present Chevrolet & GMC Truck Message Board Network

90\87Formula · 09-10-2009, 05:55 PM

I'm finally changing my 69 Fleetside from 6 lugs to 5 lugs. It's a 1/2 ton with coil springs.
Do I need to replace the U-bolts on the trailing arms or can I just use the old ones? If I need to replace them, where do you recommend buying them?

BCOWANWHEELS · 09-10-2009, 06:09 PM

Rather than going to all that trouble you could just pull your axle shafts out and send them to moser eng. In portland indiana and have them re-drilled to 5x5 bolt pattern. There very inexpensive to redrill, use your old wheel studs too. Sure would save alot of time and money. Then use 5 lug drums. Backing plates are the same.

90\87Formula · 09-10-2009, 06:16 PM

I bought a complete replacement rearend today.

oldblue1968chevy · 09-10-2009, 09:58 PM

I need to do this swap also..

is it just bolt in or do I need to readjust some kind of angle...pinion angle maybe?

Do I just bolt a 71 72 rearend in...or is there some adjustintg?

unclewatts · 09-11-2009, 04:35 AM

70 was the year that GM changed axle lengths. If your putting 71-72 axles on a 69 you should measure from the flange to the tip of the splines and get axles that are the same length.

Tx Firefighter · 09-11-2009, 07:44 AM

You guys are making this harder than it is. Unbolt the 6 lug rearend and bolt the 5 lug rearend in place. Nothing fancy needed. It's an hour job.

cdowns · 09-11-2009, 08:58 AM

i suggest getting new ubolts// local auto parts or spring store is where to get them

90\87Formula · 09-11-2009, 10:45 AM

Quote:

Originally Posted by cdowns

i suggest getting new ubolts// local auto parts or spring store is where to get them

Thank you for answering my original question.

90\87Formula · 09-11-2009, 10:48 AM

Quote:

Originally Posted by Tx Firefighter

You guys are making this harder than it is. Unbolt the 6 lug rearend and bolt the 5 lug rearend in place. Nothing fancy needed. It's an hour job.

Thanks Kevin. I was pretty sure it was a direct bolt-in. I just wasn't sure about replacing the ubolts.

Keller · 09-11-2009, 11:31 AM

Hey 90/87 Formula.. I know this is a little off topic but does your name refer to the legendary Pontiac Firebird Formula? I had a 90 Formula 350 that I learned how to wrench on.

oldblue1968chevy · 09-11-2009, 05:00 PM

thats what i thought, just wanted to makesure, thanks TXfirefighter

90\87Formula · 09-13-2009, 06:37 PM

Quote:

Originally Posted by Keller

Hey 90/87 Formula.. I know this is a little off topic but does your name refer to the legendary Pontiac Firebird Formula? I had a 90 Formula 350 that I learned how to wrench on.

Yep. The car started as a 90 coupe with the 3.1L MPFI. The 3.1 motor got trashed and I bought an 87 Formula rustbucket. I moved EVERYTHING that could be unbolted from the Formula to the coupe, thus 90/87Formula.

09-10-2009, 05:55 PM	#1
90\87Formula Registered User $90\87Formula's Avatar$ Join Date: Oct 2000 Location: Abilene Texas Posts: 1,756	Changing rearends I'm finally changing my 69 Fleetside from 6 lugs to 5 lugs. It's a 1/2 ton with coil springs. Do I need to replace the U-bolts on the trailing arms or can I just use the old ones? If I need to replace them, where do you recommend buying them? __________________ Robert Member 1532
$90\87Formula is offline$

09-10-2009, 06:09 PM	#2
BCOWANWHEELS Registered User Join Date: Nov 2006 Location: KINGSPORT,TN. Posts: 3,035	Re: Changing rearends Rather than going to all that trouble you could just pull your axle shafts out and send them to moser eng. In portland indiana and have them re-drilled to 5x5 bolt pattern. There very inexpensive to redrill, use your old wheel studs too. Sure would save alot of time and money. Then use 5 lug drums. Backing plates are the same. __________________ I BELIEVE IN JOHN 3:16 Last edited by BCOWANWHEELS; 09-10-2009 at 06:10 PM.

09-10-2009, 06:16 PM	#3
90\87Formula Registered User $90\87Formula's Avatar$ Join Date: Oct 2000 Location: Abilene Texas Posts: 1,756	Re: Changing rearends I bought a complete replacement rearend today. __________________ Robert Member 1532
$90\87Formula is offline$

09-10-2009, 09:58 PM	#4
oldblue1968chevy Grandpa in the rustmobile... Join Date: Nov 2008 Location: Spokane WA/Viola TN Posts: 11,422	Re: Changing rearends I need to do this swap also.. is it just bolt in or do I need to readjust some kind of angle...pinion angle maybe? Do I just bolt a 71 72 rearend in...or is there some adjustintg? __________________ John Goose-1968 C10 355,9.32-1CR, Vortec Heads ,262 voodoo, 3.73:1 3OTT (HS ride/beater/farm truck) http://67-72chevytrucks.com/vboard/s...d.php?t=317684 Grams 53-1953 Chevrolet Belair http://67-72chevytrucks.com/vboard/s...=1#post4327784 1969 Chevy C10 Shortbed 4.5/6?" Frame off resto http://67-72chevytrucks.com/vboard/s...d.php?t=548136 1999 Toyota Tacoma 4x4

09-11-2009, 04:35 AM	#5
unclewatts 70 Chevrolet=Obsession Join Date: Jun 2009 Location: nice ca Posts: 1,067	Re: Changing rearends 70 was the year that GM changed axle lengths. If your putting 71-72 axles on a 69 you should measure from the flange to the tip of the splines and get axles that are the same length. __________________ I'm Just like my truck. Old, Ugly and Grouchy. Except my truck starts easily in the morning and doesn't smoke! IT'S NOT EASY BEING GREEN! -Kermit the frog 1970 Chevrolet C-10 Longbed Stepside : 350, Muncie M20, 3.08 GM corp. positraction Forest green exterior/light green interior(Where all my money goes) 1996 Toyota Corolla (Parts runner)

09-11-2009, 07:44 AM	#6
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Re: Changing rearends You guys are making this harder than it is. Unbolt the 6 lug rearend and bolt the 5 lug rearend in place. Nothing fancy needed. It's an hour job. __________________ I'm on the Instagram- @Gearhead_Kevin

09-11-2009, 08:58 AM	#7
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: Changing rearends i suggest getting new ubolts// local auto parts or spring store is where to get them __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

09-11-2009, 11:31 AM	#10
Keller Registered User Join Date: Sep 2009 Location: Nashville, TN Posts: 79	Re: Changing rearends Hey 90/87 Formula.. I know this is a little off topic but does your name refer to the legendary Pontiac Firebird Formula? I had a 90 Formula 350 that I learned how to wrench on.

09-11-2009, 05:00 PM	#11
oldblue1968chevy Grandpa in the rustmobile... Join Date: Nov 2008 Location: Spokane WA/Viola TN Posts: 11,422	Re: Changing rearends thats what i thought, just wanted to makesure, thanks TXfirefighter __________________ John Goose-1968 C10 355,9.32-1CR, Vortec Heads ,262 voodoo, 3.73:1 3OTT (HS ride/beater/farm truck) http://67-72chevytrucks.com/vboard/s...d.php?t=317684 Grams 53-1953 Chevrolet Belair http://67-72chevytrucks.com/vboard/s...=1#post4327784 1969 Chevy C10 Shortbed 4.5/6?" Frame off resto http://67-72chevytrucks.com/vboard/s...d.php?t=548136 1999 Toyota Tacoma 4x4

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