I did a quick write up on the bottom of page 5 of my Cardomain site showing how I mounted the C5 'vette PBR calipers to a '70 up (or Granada) disc spindle.
C5 PBR calipers on a 70 disc spindle
- Thread starter 69gmachine
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Rusty67
Dirt-Old 20+Year Member
The late model Cobra/Mach1/Bullitt have a 1.1" rotor and a correspondingly narrow caliper as opposed to the 1.25" 'vette spec'ed caliper/rotor combo. However, yes the mounting holes are in the same place on the basket so yes, you could use the late model SN 95 PBR calipers. Unfortunately there are no after market bolt on rotors that are 1.1" that I know of, but the late model OEM rotor might work, you'll just have to mock it up to find out.
coolblue65
Founding Member
Rusty67
Dirt-Old 20+Year Member
Are the calipers actually different or did they just use thicker pads to make up the difference ? Altho, thats almost .5" which would be a lot of extra pad....
Edit:
Oh, its 1.25 not 1.5.
Thats a .15" difference. Maybe they did just use a thicker pad ?
Edit:
Oh, its 1.25 not 1.5.
Thats a .15" difference. Maybe they did just use a thicker pad ?
nope the Vette actually had an optional brake system that used a thinner rotor with the same style of caliper but it's different too. now that may be the same caliper that was used on the late Mach1 and Cobra
coolblue65
Founding Member
never heard that one, all C5 rotors are the same that I have seen and used on mine or my father's vette. The only options for brakes on C5's were part of the Z06 package and the only difference with that one is the powdercoated calipers.
there was an option for 12" rotors and 13" rotors. IIRC the 12" rotor was the thicker one.
Rusty67
Dirt-Old 20+Year Member
In that case, I'd imagine that the 13" setup uses the same caliper as the Cobra type caliper.
Are you using 12" or 13" gmachine ?
Are you using 12" or 13" gmachine ?
coolblue65
Founding Member
Ah, well your half right, here is the run down on corvette brakes:
For the C4's (84-96) the stock rotor was a 12" and there was an option 'J55' for Heavy Duty 13" brakes starting in '89 when the Zr-1 came out (13" were stock on Zr-1's), they were also stock on the Grand Sport, and the Collectors Addition in '96. The C4 calipers were all of the quick-release/change design that you see on most Bear kits.
When the C5's came out in '97 there were no options for brakes, they were all 13" with the PBR calipers like 69gmachine used. The only option if you will came as part of the Z06 package and that was just powder coated brakes.
As a side not the C5 brakes are vastly superior to the C4 brakes (stock or HD), I put the C5 brake rotors and calipers on my C4 Vette.
Here are a couple pics comparing C4 to C5 brakes:
I used to own a C4 and I can tell you C4 brakes suck (but the ZR-1/Grand Sport brakes are decent). The C5 brakes are all the same and are way better. In fact, most C6 guys who track their cars retrofit the C5 brakes mostly because they are dirt cheap (rotors are like $22 at NAPA) compared to the new brakes but also because they work. The C5 calipers will start to distort under heavy braking, though. Overall, the C5 brakes are pretty awesome.
My rotors are 1.25 x 12 3/16ths with an 8x7 bolt circle, which is an off the shelf size used in asphalt stock car racing. This diameter allows the C5 basket to be located on the Ford disc spindle using the OEM lower caliper bracket boss. The hole just needs to be opened up slightly.
Thanks coolblue65 for the nice pics and the scoop on the different C4 and C5 'vette offerings.
It wasn't hard to adapt the C5 calipers. Given the low cost, they're readily available and track specific compound pads are also available, they're in a class by themselves for best bang for the buck IMO.
ok well, then it looks like i'll be going for the 70 LTD rotors from RotorPros on ebay and some C5 calipers. the LTD rotor is slightly smaller at 1.185" than the vette rotor at 1.26" but that's only .075 difference so it should work just fine people use 99-up mustang GT/V6 calipers on granada rotors all the time and there is a bigger difference there at over .100" so things should work out great.
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