Have the rotors turned and checked to see if they are in specs. Remove the drums and all brake hardware from the car. Disconnect the metal line from the flexible line that runs to the wheel cylinder, this can be difficult flare wrenchs may help or in my case I had to resort to vise grips. Remove the nuts holding on the backing plate and spindle. Remove all the bolts , there is a gotcha here one of the lower bolts may hit a 90 degree turned spacer between the lower control arm and the strut rod, save yourself the hour I spent removing the strut rod and stripping a bolt and take a hacksaw and cut off the bolt, you can use one from the donor car. Since the bolts come in from the front on the disc system this will not be a problem in reassembly. Remove the master cylinder, power booster and all front metal brake lines as well as the brake pressure warning unit.
Install the spindles, backing plates and mounting brackets, if you watched how everything came off this should be easy. The calipers should mount toward the top front of the rotor. Mount the rotors onto the spindles and secure the bearings with the washer, nut and cotter pin and put on dust cap. Connect the new flexible brake lines to the calipers, another gotcha here, if you car is equipped with the loveable trunnions, like mine, then the metal part of this brake line may want to run right through the middle of your trunnion. I overcame this problem with a tubing bender, if you have to do this connect the line to the caliper first then bend the brake line down and toward the middle of the car to run behind the trunnion. Bend it a little at a time and keep setting the caliper in place until the line is no longer touching the trunnion. Others have told me this was not a problem when they did the install, I have to assume that the brakes lines come out of the calipers at different angles depending on who anufactured the calipers you are using, if you don't have this problem it will save you about an hour on the install. Install caliper with brake pads. Connect the free end of the flexible line to the mounting plate inside the wheel well. Install the power booster from donor car being sure to connect the vacuum line, this is an excellent time to clean it up and paint it. Install the master cylinder and be sure to bench bleed it first. Run all the metal brake lines that you removed to their appropriate places and connect securely, do not mount the proportioning valve yet, let it hang by the brake lines until you have finished. The brake lines may require some custom bending to mount to the firewall but this isn't too difficult, just be careful not to crimp or break them. Once you have the brake lines securely fastened then secure the proportioning valve inside the engine compartment.
Lastly, bleed the brakes on all four wheels, check for leaks, and test for stopping power.
Please also note that for true balance on the brakes the braking system with disc brakes were designed to be used with 10" rear brakes which I believe came on all disc brake equipped cars and all V8 equipped cars, the I6s, with front drums, came with 9" rears. There are some people running disc front with the 9" rear brakes and working fine, but to accomplish optimum balance between front and rear if the rear brakes are not already 10" drums these should be swapped as well (this swap is not covered here).
Many people also mentioned the swap of early disc (70 and back four piston caliper non vented rotors) to late disc (71 and up single piston calipers with vented rotors). This is accomplished the same as above except the master cylinder and power booster are identical to the later model cars and the proportioning valve and metal brakes lines should work just fine. All parts at the wheel including spindles, backing plates, mounting brackets, calipers, rotors, and flexible brakes lines should all be replaced as above.
Jeff Barfield
jrbarfield@mindspring.com
69 Javelin SST 343 (Now with disc brakes)