Third Generation GM F-Body Brake Upgrade – FAQ (3/9)

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Q: What is a hub?
A: If you look at the picture below you will see a side by side comparison of the Camaro / Firbird F-body rotor and the C4 rotor. As you can see the Corvette C4 rotor does not have that center section. That center section is physically part of the F-body rotor and mounts on the spindle. To mount the C4 rotor on a third generation f-body you much machine down a F-body rotor to just that center section then you can mount the Corvette C4 rotor over the machined down hub.

Comparison between GM F-body rotors which have built-in hubs and C4 Corvette rotors which do not.


Q: What swap options are discussed mainly in this article?
A: I will mainly discuss on the Corvette C4 and fourthgen F-body Camaro \ Firebird LS1 brake swaps because these are the swaps I have spent the most time developing. Another very common brake swap is the Corvette C5 or C6 brake swap which I will discuss lightly. All brake swaps have similar spindle modification and hub design so almost all of this information can be applied to any brake swap.

Q: What about the spindle bracket?
A: I have designed brackets for use with Corvette C4 and Camaro 98-2002 “LS1” Brakes. I have also posted the bracket design used to mount C5 brakes, see the Bracket Design page.

Q: Brake Do’s and Don’ts
– Do NOT make your spindle bracket out of aluminum!
– Always round off edges on your spindle brackets to reduce stress points.
– When replacing rotors or pads always perform proper braking in procedures before putting your brakes through its paces. I know it’s tempting to slam on the brakes to test out your new setup but it’s a lot better to perform many gradual and normal stops first to start a wear pattern going first.
– It is recommended to safety wire all bolts on the brake setup.


Upgrading to Corvette 88-96 C4 Brakes Questions

Q: What brake options came on the C4 corvette?
A: There are four brake setups that came on the C4 corvette. The first is a fixed caliper design that came on the 84-87 corvettes which I will not discuss swapping because they are not worth the effort. In 88 GM put a 12-inch brake setup with a dual piston aluminum PBR caliper on the C4’s. This setup is called the C4 NON-HD setup or non heavy duty. Then later in the production of the C4, GM came out with an optional 13-inch brake setup for the Corvette which is called the C4 HD or Heavy Duty. The final brake packet found on a limited number of Corvettes is the Grand Sport or GS setup. The GS model features a beefier caliper. The GS brake package uses the same rotor as the C4-HD brake setup.

Q: Will the C4 setup clear my stock 15 inch Camaro wheels?
A: The 12 inch NON-HD setup will, the HD 13 inch setup will not.

Q: Will my stock spare clear the C4 brake setup?
A: No it will rub the caliper.

Q: What proportioning valve and master cylinder combo will I need with the C4 brakes?
A: You can use your factory drum or disc master cylinder but it is recommended to switch to the 1LE Master cylinder and proportioning valve combo. For part numbers and more information CLICK HERE.

Q: Will I need different brake hoses?
A: No, the stock hoses will work. I would upgrade to braided hoses while you have everything off.

Q: What year and model corvette can I get these brakes off of?
A: You need to get them off a 1988-1996 C4 Corvette.

Q: What outer diameter should I mill my rotor “Hub” down to?
A: Baer’s hub has a diameter of 5.95 inches where the rotor mounts. I recommend you get as close to that as possible.

Q: What is the difference between the 1LE and C4 brakes?
A: The C4 NON-HD brakes have thinner rotors, 0.81 inch, then the 1LE (1.1 inch) rotors. The C4 NON-HD caliper also has a smaller rotor opening to accommodate the thinner C4 rotor. The C4 HD 13 inch brakes have about the same thickness router as the 1LE but have a 1 inch larger diameter.

Q: Can I use a 1LE rotor so I don’t have to fabricate a hub?
A: No, the C4 NON-HD caliper has a smaller rotor opening then the 1LE caliper. The C4 NON-HD and HD caliper carrier is not bent like the 1LE so it will not clear the 1LE rotor. For some pictures comparing the two calipers and caliper carries CLICK HERE

Q: What about the spindle bracket?
A: For the C4 13 inch HD setup you will need to use my bracket design. For the C4 12 inch NON-HD there are 2 designs you can use; Alloy’s or mine. Both are discussed and pictures in this thread. You should use Alloy’s bracket if you would like to use C4 front rotors. If you use my bracket design you will need to use C4 rear rotors. I posted dimension and CAD file of my bracket design on the bracket design page on the left menu.

Q: What is the difference between the C4 front and rear rotors?
A: The C4 12 inch NON-HD front and rear rotors are about the same except for offset. They are the same thickness and there shouldn’t be a noticeable performance difference between the two rotors. The rear rotors allow for more room for a bracket so they will work with my bracket design. If you want the 13 inch C4 HD brakes you will need to use the C4 13 inch HD front rotors and a thirdgen f-body 1LE rotor as a hub.


1998-2002 Fourth Generation F-body “LS1” Brakes Questions

Q: Why is this brake setup called “LS1” brakes?
A: It is a lot easier to type LS1 instead of “1998-2002 Fourthgen Camaro/Firebird”. In 1998 GM introduced the LS1 engine into the F-bodies, that same year they also put bigger brakes and a few other goodies. I am just using LS1 as an easy way to identify the 12-inch, dual piston caliper brake setup on these cars. It is important to note that the “LS1” brakes also came on the V6 1998-2002 Camaro / Firebirds also.

Q: Will the LS1 setup clear my stock 15 or 16 inch wheels?
A: This setup will not clear any 15 inch rims that came stock on thirdgens. Here are the rims that will work:
– Early model & Late model IROC 16 inch rims
– Some GTA and Firebird rims work some don’t you will need to research that on
Some firebird/GTA rims need shims to space out the wheel, this can be done with GM part number 14091902 (.030 inches thick).

Q: Will my stock spare clear the LS1 brake setup?
A: No it will rub the caliper

Q: What proportioning valve and master cylinder combo will I need to use the LS1 brakes?
A: You can use your factor drum or disc master cylinder and it is recommended to switch to an 1LE proportioning valve.

Q: What brake hoses should I use?
A: The stock hoses will work.

Q: What year Camaro / Firebird can I get these brakes off of?
A: All 1998-2002 Camaro / Firebirds came with the front 12 inch, dual piston caliper brake setup.

Q: What outer diameter should I take hub down to?
A: You should take the LS1 rotor with you to the machine shop and have them machine down the hub until it fits in the hat of the LS1 rotor. My hubs have an outer diameter of 5.85 inches.

Q: What is the difference between the LS1 and C5 brake calipers?
A: They are based off the same design but there are more differences then I originally thought. The C5 caliper has stiffing / cooling ribs that extend the full length of the caliper, where the LS1 caliper only has them on the back (as you can see in the picture below). The C5 caliper is produced by a method called pressure casting and the LS1 caliper is produced by gravity casting. This means the C5 caliper is stronger and more durable.

Q: Are the C5 and LS1 caliper interchangeable?
A: Yes, You can go to a parts store and purchase a C5 caliper and use it on a LS1 abutment bracket (mounting bracket, sometimes called a caliper carrier). The C5 and LS1 calipers abutment brackets have different mounting hole positions though so only the calipers are interchangeable without making a new spindle bracket.


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Page created: January 2006
Page content last updated: 06-21-2009

2 thoughts on “Third Generation GM F-Body Brake Upgrade – FAQ (3/9)”

  1. What parts do you need to swap from C4 non HD to C4 HD…..?
    I have rotors – it looks like the caliper – pads and caliper mount all need to be changed.

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