The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 06-25-2014, 05:12 AM   #1
donthekawguy
Registered User
 
donthekawguy's Avatar
 
Join Date: Aug 2012
Location: Rathdrum ID
Posts: 1,129
brake rotor ?

I'm coming over from the 60-66 truck side with a question. I got some CPP 2 inch drop spindles from Summit. They called for using the 1.25 inch thick rotors. I got the rotors and calipers and I'm trying to put them on my truck. The rotors fit fine but I'm having trouble with the calipers. I might have been sent the wrong spindles. What trucks had the 1 inch thick rotors and what trucks had the 1.25 inch thick rotors?
__________________
66 shorty
donthekawguy is offline   Reply With Quote
Old 06-25-2014, 06:35 AM   #2
lolife99
67-72 parts collector,…
 
lolife99's Avatar
 
Join Date: Nov 2002
Location: Mid-MO
Posts: 22,700
Re: brake rotor ?

No rhyme or reason on the truck year.
I've seen a lot of different engine combos and option packages for these brakes. 1" rotors didn't happen until 81-87,... But you could also still get the 1.25" rotors found in the 73-80 trucks.
__________________
Keith

Convert to disc brakes.
http://67-72chevytrucks.com/vboard/s...d.php?t=444823
lolife99 is offline   Reply With Quote
Old 06-25-2014, 07:52 AM   #3
Keith Seymore
Registered User
 
Keith Seymore's Avatar
 
Join Date: May 2009
Location: Motor City
Posts: 9,226
Re: brake rotor ?

Here is the brake system release chart for '87, which shows the rotor usages. 1" rotors are on the super light duty C10's, like manual brakes or the 5600 lb GVW JB3 power brake system.

Fortunately (or unfortunately, depending on your perspective) we did not build many of those.

K

__________________
Chevrolet Flint Assembly
1979-1986
GM Full Size Truck Engineering
1986 - 2019
Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926
My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524
Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/
Keith Seymore is offline   Reply With Quote
Old 06-25-2014, 11:33 AM   #4
1977cheyenne_C10
Registered User
 
1977cheyenne_C10's Avatar
 
Join Date: Jan 2012
Location: Palmdale CA
Posts: 303
Re: brake rotor ?

My 77 Gmc heavy half has 1.25 rotors
1977cheyenne_C10 is offline   Reply With Quote
Old 06-25-2014, 11:51 AM   #5
piecesparts
Parts and more parts
 
piecesparts's Avatar
 
Join Date: Nov 2003
Location: Lebo, Kansas (middle of nowhere
Posts: 6,821
Re: brake rotor ?

My 84 GMC and my Son's 86 Chevy, both have the 1.25 rotors.
__________________
Frank
piecesparts is offline   Reply With Quote
Old 06-25-2014, 12:01 PM   #6
1977cheyenne_C10
Registered User
 
1977cheyenne_C10's Avatar
 
Join Date: Jan 2012
Location: Palmdale CA
Posts: 303
Re: brake rotor ?

Keith is there a reason why General Motors put two different rotor size?
1977cheyenne_C10 is offline   Reply With Quote
Old 06-25-2014, 12:02 PM   #7
Keith Seymore
Registered User
 
Keith Seymore's Avatar
 
Join Date: May 2009
Location: Motor City
Posts: 9,226
Re: brake rotor ?

Quote:
Originally Posted by 1977cheyenne_C10 View Post
Keith is there a reason why General Motors put two different rotor size?
To save piece cost.

With trucks they are always trying to have a "value leader", so they can advertise the cheapest MSRP. Cutting corners every little bit helps.

K
__________________
Chevrolet Flint Assembly
1979-1986
GM Full Size Truck Engineering
1986 - 2019
Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926
My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524
Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/
Keith Seymore is offline   Reply With Quote
Old 06-25-2014, 05:15 PM   #8
MalibuSSwagon
Registered User
 
Join Date: Sep 2009
Location: Weare,NH
Posts: 1,592
Re: brake rotor ?

I just swapped over to 1.25 rotors on my C10 (along with the drop spindles) the cross reference on calipers for my truck went back to 1979. Looking on Rockauto for calipers and rotors, it is very confusing when trying to pick out the correct big rotors and calipers for a 81+ C10.

So, when I went to my local O'Reillys, because shipping is insane on these heavy pieces, I asked for rotors and calipers for a 1979 C10, since 1.25 was the only option that year, the parts jockey can't screw it up. The brake lines will bolt up.

Yes, there are different calipers for each size rotors, the 1.25 calipers are .25 inches wider than the 1.00 calipers. Weird right? haha. You'll know if you have the wrong calipers because you'll load up the brake pads and they won't fit over the rotor.
MalibuSSwagon is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 09:39 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com