Showstopper - Technical Article - Chevy High Performance Magazine

With the stock power brake booster removed, the two lower holes must be drilled (reamed) out to accept the four studs on the booster. To precisely locate these holes, we used the supplied paper template and marked the firewall.	The center opening also needs to be reamed at the bottom area , as well as the two lower stud holes.	For four-wheel disc brake applications, this nut, pin, and internal spring must be removed from the combination valve in order to provide the proper front-to-rear bias.
Once removed, you'll need to insert this plug.	After bench-bleeding the master cylinder, we installed the supplied brake lines so one master cylinder outlet goes to the front and the other to the rear, splitting the system in series with the new combination valve. While this may sound confusing, an easy-to-follow schematic is provided that's unique to the master cylinder for your specific kit. The lines from the combination valve to the frame are not included.	After installing the master and booster assembly into the car, we reattached the clevis at the brake pedal and hooked up the brake lines.
The rear disc brake kit comes with caliper mounting brackets, calipers with a parking brake mechanism and pads, 11-inch multi-pattern rotors (either Ford or GM pattern), mounting hardware, rear hoses with hose bolts, and parking-brake cables.	Both axles needed to be removed to install the rear disc kit. To do that, the pin and two C-clips must first be removed from the center carrier.	With the drums removed, the axles simply slide out. In order to use the GM rotors, you'll have to turn the stock axle flanges down to 5 7/8-inch o.d. Standard factory-type axles are easily machined on a lathe, but if you're using aftermarket axles, be sure to consult the manufacturer to see if they have heat-treated flanges before attempting to machine them. If they are heat-treated, now's the time to ask the manufacturer for a recommendation.
We removed the metal brake lines to the wheel cylinders, the existing backing plates, and the parking brake cables from under the car.	As shown in this mock-up example, the rear calipers, bleeder screw, and parking brake cable (when mounted on the bracket) should be installed so that they are positioned at the top. The attached parking-brake cables will route to the center of the vehicle, where they can be connected to the existing parking-brake system.	Secure everything tightly and check for frame clearance throughout full frame travel. Rotate the rotor and check for any interference. The rotor should run true. Remember to reinstall the carrier slide pin, bolt, and rearend cover, and add gear oil.
Now make all the final connections and bleed the entire brake system. After the rear wheels are mounted, you'll want to check rear wheel clearance, since the new rotors will space the wheels out about 1/4 inch. Once everything is bled and installed to spec, drive the car easily and test the brake system on a deserted road...	...If your brake pedal is low, check the accompanying tech tip. Finally, once everything is completed, be easy on the brakes for the next several hundred miles to break in the new rotors and seat the pads.

Tech Tip
If you are using Cadillac Eldorado-style rear calipers (as we did), there are some important things you should know. These rear calipers adjust off the parking brake, which is incorporated into the caliper. You must set the parking brake every time you park the car so that you utilize a one-way clutch inside the caliper piston. When the parking brake is applied, the clutch senses when there is a 0.030-inch or greater clearance between the friction material and the rotor on the inboard side. When there is in excess of 0.030 inch, the clutch turns inside the piston, adjusting it out, keeping the rear brakes adjusted. If you do not set your parking brake every time, you will start to lose brake pedal (low and spongy) and the adjuster mechanism will not work.