A while ago I swapped in a set of 88 camaro rear discs onto mr 84 S10, The S10 axle was way different, as far as backing plate mounting goes, so I had to cut fab drill, all that. The caliper brakets for the F-body have a 4 bolt pattern that's not square, When I had the 12 bolt out of my car, I noticed it has the same looking pattern for the drum backing plates.

My Question is, will the disc backing plates bolt right on to the 12 bolt? Has anyone done this?
If so, all it would take to finish the conversion, would be to turn the axle flanges, to fit the rotors over, like my S10.

Is it that easy?

I think the 12 bolt took the same brakes as the 10 bolt did, and the 3rd gen Camaro rear disc are 'supposed' to bolt on to the older 10 bolt rears, because they have the same pattern and spacing. I guess you could measure it all, and then tell us for sure if it works

The only thing I'd be concerned about is matching the front calipers to the rears. The 88 Camaro rear calipers were matched to a front of 2.5" diameter, same as the S10, and were only 1 7/8" diameter themselves. If your front calipers on your current project displace quite a bit more, you might not get much use of the rear on the street. I think the earlier 3rd gen Camaros used a 2 1/8" rear caliper, which matches well to a front GM 2 15/16 caliper. I dont know if they use the same bracket, but they might.
Just a heads up

Thanks man. I've ordered parts to do the same B-Body brake upgrade I did on my S10, for the 12in fronts, and would like to match with the 1LE 12" rears. On my S10 I used the smaller 10.5in rears.

I didn't realize there's a method to balancing caliper piston size front to back and would appreciate more info on this.

I'm gonna look into this right away, I've got a line on a disc rear allready. Can anyone tell me if the 4th gen rears are diff than 3rd gen?

I think some if not all 4th gen didnt use the ratcheting style caliper, but some had a lever type, and later used a drum inside the rotor like the Corvette (sort of). Even that type I think bolts on, according to the Fbody sites. They use even smaller caliper pistons though.

The balancing has to do alot with what the vehicle is used for, and front/rear weights. From looking at many different stock systems, most RWD front engine vehicles use rear calipers of about 50-70% of the Area of the fronts. This gives about a 65:35 front:rear ratio (add front and rear areas together and find percentage of total). FWD cars go with closer to an 80:20, and so use much smaller rears in comparison to front calipers.

The rotor diameter has much less effect on brake torque than the piston size. Large rotor diameter and thickness help reduce brake fade because the excess metal absorbs and dissipates the heat better. The larger diameter rotor gives a bit more leverage, but it doesn't compare much to the clamping force of a piston. Imagine the length of the lever needed to lift a car manually, compared to hydraulic jack pistons.

Small caliper pistons are fine if matched front and rear, and to master size and proportioning valve for vehicle weight. A small piston can clamp as hard as a large one with the right master cylinder.

BTW, these #s are all about area, Not diameter.

Read through some of stoptech's white papers online and you will find a wealth of info on disc/disc balance. Outlawdisc has some good info on the basic math on their FAQ page.

Well I got the caliper brackets for a 90 camaro with high performance option, and they bolted right on. So now I have to get the other half of the caliper brackets, and calipers, to see if they clear the shocks.

Lookin' good so far.

So, if I read this right I should be able to swipe the back disk brakes off my 87 IROC (donor car for my 34 2dr Sedan project) and bolt them up to the 65 12 bolt chevelle rear end that is in my El Camino?

Matthew

Really the only difference in physical size of a 4th gen rear as compared to a 3rd gen rear is the width. I am currently building a '83 Camaro and am using a fourth gen rear end. It is about 2 inches wider on each side meaning different wheel sizes will be needed (i.e. more backspacing). Other than gear options I think this is the only difference because everything else bolted right up.

A little more info on this. It's going slow, but I've got so much going on right now. Got the other caliper brackets that go around the rotor and hold the caliper to the first bracket. Found it has to be shimmed a little as do the camaro axles. and GM carries the shims. I purchased rotors for a 90 Camaro, which necessitates turning the axle flange down a bit to clear. Though mine only needed to be beveled. I looked at 93-97 Camaro rotors which I've been told don't require turning to fit. They looked like they would slip right on, but were twice the price and of poorer quality from the same company (Wagner)

Now I'm just looking for a place that will sell me the calipers without charging me core. Then we'll see if it clears the shocks.

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