I used stock drum brake spindles to convert to 12” rotors.
This may look like a pile of junk, but it is great donor part. Reuse the drum spindles, steering arm, hub and bolts/ hardware.
I am using 98-02 Camaro front rotors drilled/slot and 2 piston calipers. The drum hubs need to be turned. Turn them down from 6.2” to less than 5.83” diameter. While they were in the lathe, I faced off “trued-up” the face that the rotor will press against when the wheels are on.
I added grease fittings in to be able to push grease through the bearings more easily. Also pressed in long wheel studs 7/16-20x2.875” long with .47 knurls.
Note: support back side with a tube and hammer in the studs, don’t use a hydraulic press, you will warp the hub! Been there done that.
I bought these brackets on Ebay from Metaltek Manufacturing “GM A F X BODY CHEVELLE NOVA CAMARO DISC BRAKE SWAP BRACKETS #14001A” for $35.
They are ¼” thick steel. The upper mounting bolt that goes into the spindle is 5/8"-18, 1-1/2" Long found them on McMaster-Carr part number 91286A435 with a lock washer.
Next, it is real important that the bracket is mounted parallel to the plane that the rotor spins on. For when you use drum brake spindles it is essential that you put a spacer under the bracket at the lower mounting position. I point out the location in the picture. I used 2 washers 316ss 7/16, .055-.069 thick McMaster-Carr part number 90107A032. If you use disc brake spindles, you do not need these but instead you need a spacer at the top mounting location to insure the bracket is true.
Reused the stock ½” bottom bolts that go through the steering arm.
Install the 2002 Camaro caliper brackets to the fabricated conversion brackets using two grade 8.8, 12mm x 1.75 x 12mm long bolts and lock washers commonly found at a local hardware store.
One option is to put one washer under the bracket as shown in the pic above, at each of the 2 bolts to bring it out center. It may vary on each individual build. Each set-up may vary a little. (316ss 7/16, .055-.069 thick McMaster-Carr part number 90107A032.)
Another option, that I chose, was to add a spacer between the hub and the rotor.
I cut the centers out of a set of old brake drums.
Mount everything up correctly. Install bearings and hub, properly adjust big spindle nut, put spacer on hub, put rotor on and some lug nits facing backwards so that the taper is facing out and the flat part is facing in. This is done so that the taper doesn’t try to force a misalignment between the rotor and the studs since the Camaro rotors used metric lugs, they are not perfectly on the same bolt circle. Tighten down the lug nuts to insure nothing is warped or not squeezed together properly. Mount the caliper with caliper bracket and brake pads assembly to the new adapter brackets that are already mounted to the spindle.