Rear Disk Brakes

I mocked up the rear disc brakes inna box tonight. I think it looks like a good setup. Only problem I ran into was my old skool 15x10 Keystone Klassics will not clear the caliper. So back to the drawing board on wheels. unless newer ones are clearanced for disc.

the kit comes with extra shims to help center the caliper

Also will need to run longer wheel studs. The rotor slipped over the axle flange with just a little clean up with a file. The clearance issue made me wonder if even the caddy parts would only allow newer wheels or just narrower ones with less back spacing.

Digz, I'm running 80 Pontiac rally wheels with the Caddy setup. They are from a disc brake car so it was no problem.

Your kit looks good!

Later,
Rip

Nice looking kit Digz, I'm just about ready to use the parts that RIP had used! I have everything ready to go, once I get the time to do so!!??
B.W.

Yep, me too. I started collecting the parts a few days after Donivan started this thread. Have to find new JY's in Jax. Fla. but my parts collection is almost complete. Not any earlies in the JY's here that I have found yet but just started looking. What I have found is a lot of old caddy's, Chevelle's and Pontiac's (GTO's) in the JY's here.... Even found a 68/69 2 door Tempest with a posi rear... In great condition just sitting in the back of one lot. Anyway, I'll be searching for new yards and going to check one out today I was told about that only carry's 60's vehicles about 40mi away..... Crossing my fingers for some earlies...

I took it all back apart tonight and popped the seals and bearings on the axle tubes, there is alot of corrosion in this rear end, I flushed everything and will be replacing the axle bearings and all of the seals, Once i get the axles clipped back in I will have an exact idea of how bad the wheels are hitting, I kind of think I may be able to stick a 1/4" wheel spacers in and clear it. Its gonna work one way or another! Might even gain some by grinding the calipers like Don said. If that big wide spot in the center of the wheels was 1/2 narrower it would have been to easy It will be a few days , work has really picked up now. Thank goodness!

RipVanArkie wrote:I rotated the brackets about 35* and marked my holes. I used the Cadillac rotors as well, I just milled the wheel flange down 1/8" so it would slip inside the hat. You will need a 1/8" spacer behind the rotor so everything lines up.
Rip

So Rip,
What exactly do you mean that you will need a 1/8 th spacer? I'm just tearing in to my conversion!!
B.W.

Curious minds need to know??? lol
B.W.

If I can toss something in here, On the kit I got it supplies shims to adjust the caliper bracket in or out what I think would be 1/4 of an inch one way or the other because the axle flange is a fixed point, Kit bracket mounts on the inside, The caddy bracket on the outside, the goal of the shims is to make the outer pad lightly contact the outward face of the rotor. Not being able to move the caddy bracket inwards one would have to move the rotor outwards or move the axle flange in. Or,,, and I havent measured the hieght of the my rotors yet,, find a rotor that is not as tall. I will measure the kit rotors today , I am curious myself if they are also a knock off of the caddy rotors as are the calipers in the kit

The rotor sits too close to the inside of the bracket. A 1/8" spacer behind the rotor centered it perfectly for my conversion. This was also true on the 72 Nova rear that I converted.

Hope this helps, you guys are well on your way.

Later,
Rip

SO...the question is, where to obtain an 1/8th spacer??? lol I got started on this "Upgrade" this weekend and have everything off and just about ready to go back on!! lol I tried the S-10 Rotors and they just about seem to work? What did you use Rip? My driver's side fits, but the passenger side hub needs to be turned down about 1/8th "!

B.W.

Here is a difference I think would be an adVantage to the caddy system Don,
If my research is right and you guys can tell me, the caddy rotors are 10.5 inches in dia. the Kit rotors are slightly over 11 inches more like an 80's firebird

This is where I am running in to trouble using Old Skool rims I think in the 10inch widths, so maybe by using the caddy set up it opens up a larger wheel selection?
The overall hieght of the rotor in the kit is 2.250 and the distance from the outside of the hat to the face of the rotor is 1.250

On the plus side the kit rotor fits over the axle hub with little effort.
The thickness of the rotor at the axle hub is .295 give or take.

So using the kit I may be doomed to going with 16 inch wheels or heaven forbid narrower tires/wheels I have a set of stock 15x7 pontiac wheels to try on and will post the results so if someone else does this they will have a good idea of what they are up against.

I just now measured the S-10 rotor I have and it measures at 11 3/16th's!

Sorry, photo bucket cuts off the image as it is way too large!! lol

Whats the I.D B.W. ? mine is 6 and a 1/4 .

I'm going to wager your going to need to use the caddy rotors as well

Well, I used the rotors from the same caddy the brackets and calipers came from.

For spacers I used large stainless flat washers 1'8" thick. This is not what I had intended to use permanently, but we're 2-3 years and tens of thousands of miles down the road and I simply have had zero problems with this.

One could actually cut the center out of their old drum and use it for the spacer if one cannot be found otherwise.

One might use an 11" rotor if the bracket is pushed all the way out before drilling and bolting it to the axle tube.

I'm sure that there are many different ways to make this conversion with the JY parts. I just happened to have the parts-car on hand and decided to see if it would all fit and it did.

I am glad I have been able to help my fellow vanners but most of the credit belongs to GM who has forgotten how to keep things simple and interchangeable.

Whatever you do, do it safely and improve the process whenever you can then pass the knowledge on to the rest of us.

When I did the front disc brakes on my 64 I couldn't imagine a better, easier way, but even that process has been improved by one of us, m1dadio!

Good luck!

Later,
Rip

Digz, sorry I'm not at my garage to get an Inner ID measurement! I have reason to believe that the S-10 and Caddy are the same though These rotors were intended for the front, as I want to change out BZ's Disc design, which I have on now, for the M1D's designed ones which I have all the parts ready for! Gotta love these "Earlies" to put all of this labor and $$$$ into them!!! But really, the bottom line is.......I wanted the best braking system, to insure my stopping ability!!!! Next up...the Power Steering upgrade!!! lol
B.W.

I learned today that the rotors that came in the rear disc kit are the same as the ones used in the front conversion 79-81 firebird. I have started on my front end makeover as well.

Just a follow up on wheels, I had to run 1/2 inch wheel spacers to get my old skool Keystones (15x10's with 3.5" backspace) to clear the calipers on the rear, I have some mid 70's pontiac ralleys 15x7 (steel wheels with a 4" backspace), they clear it all, front and rear, easily with more of a back space than the 15x10s

This is becoming my fav. thread....... lots of great info here....