If you own a GM truck from the '60s through to the late '80s with a 10-bolt or 12-bolt rear axle, upgrading to rear disc brakes has never been easier. Rear disc brakes provide a range of advantages over traditional drum brakes, most notably increased stopping power and increased brake fade resistance. The 1012RWBK-12 Big Brake Kit from Classic Performance Products is perfect for the classic truck owner who wants four wheel disc brakes along with the great looks of larger cross-drilled rotors without the need to change the entire brake system.
This rear disc brake conversion kit from CPP was designed to convert as easy as possible while affording the truck owner the ability to have a better performing and better looking brake system. The key is the development of a rear axle caliper bracket. The kit includes 12-inch diameter cross drilled rear rotors, caliper brackets, loaded calipers, differential cover gaskets, new rubber and hard brake lines, brake hose tabs and clamps, parking brake cable, wheel studs and all necessary hardware to get the job done. The kits are available for five or six lug applications and can be coordinated with converting the axle bolt pattern from six to five lug.
The process will involves removing the rear axles from the housing as well as bleeding and recharging the brake system when complete. If you are not inclined to do this yourself, seek the services of a qualified mechanic. The following steps highlight the conversion process.
CLA SSIC PERFORMANCE PRODUCTS, INC.
175 E. FREEDOM AVE., DEPT TEN
ANAHEIM, CA 92801
(714) 522-2000
 First step is to remove loosen the differential cover bolts. |  Place a container under the axle housing and pry open the differential cover just enough so that the gear oil can be drained out with making a mess. |  Once all of the gear oil has drained, remove the differential cover. |
 Remove the wheels. |  The factory drum brake housing should slide right off of the wheel studs. |  Remove pinion shaft locking pin from the rear end gear unit. |
 Carefully slide the pinion shaft out to reveal the axle locking clips. Remove axle clips. |  Remove the axles. This is the ideal time to install new axles with a different bolt pattern, such as switching from six lug to five lug. |  Remove the hard brake line from the drum brake backing plate. |
 Remove the four backing plate bolts which secure the drum brake assembly to the axle housing flange. |  Remove the brake assembly from the axle housing. |  Unbolt and remove the brake hard lines from the axle. |
 Install the new caliper brackets onto the axle housing. |  If the new wheel studs are longer than your factory studs, install the new studs into the axle, then slide the axle into the rear end to check to make sure the caliper bracket hardware clears the wheel stud heads with the axle fully pushed in. |  Permanently tighten the caliper bracket hardware. |
 Slide the new and larger CPP cross-drilled rotors onto the wheel studs. |  |  Install the loaded calipers onto the disc and bracket. It is important to make sure the bleeder valve is at the top and the brake line connection at the bottom. |
 Install the caliper locking pins through the outer mounting ears, into the bracket and into the opposite side caliper mounting stud ear. |  Tighten both caliper mounting studs. |  Check to make sure both axles are fully pushed in, which they should be in order for the caliper to have installed properly. Install the axle C-clips to secure the axles. |
 Re-install the pinion shaft and secure. |  Use a scraper to remove the old gasket material from the housing. |  An aggressive cleaner like carb or brake cleaner can be used to completely clean off and dry the differential cover surface. |
 Apply a gasket sealer to the housing surface. |  Place one of the provided differential gaskets onto the housing. |  Install the differential cover and all hardware, then tighten to specs. |
 |  Install the provided new parking brake cable. Some vehicles which already had a parking brake my not need to use the new cable. |  Remove the parking brake spring from the caliper. |
 The parking brake uses a manual compression arm which can be adjusted to get a really good pedal for braking. |  Push the lever forward to force the pads to press against the rotor. Ideally you want the pads to touch the rotor, so if you have to move the lever forward much, this means it needs to be adjusted. |  Remove the bolt which secures the leverage arm to the caliper. |
 Turn the lever forward several times to make the pads press against the rotor. |  This is what you want to see, both pads pressing against the rotor. |  Once the pads are seated against the rotor as desired, reinstall the lever in the relaxed position on the caliper. Now when you depress the parking brake pedal, you will force the pads to bite aggressively and insure the vehicle won't move. |
 Reinstall the parking brake spring. |  Install the parking brake cable into the spring, pushing it through the spring to where it attaches to the leverage arm. |  Attach the front end of the parking brake cable to the existing connection clamp just under the cab. |
 Install the provided brake tab clamp around the axle tube just inboard of the brakes as shown. |  Install the provided 10mm banjo bolt and two copper crush washers as shown. One washer on either side of the banjo fitting. |  Install the brake hose onto the caliper. Do not permanently tighten the bolt until the entire installation has been complete. |
 New ready-to-install axle brake hard lines are installed onto the housing. The hard lines can be tweaked in shape a little to make the hard lines rest firm against housing. |  Install the hard line fitting into the brake line block attached to the passenger side of the axle housing. |  Use the factory axle housing clamps to secure the hard lines. |
 Install the caliper brake hose tab with the small hole placed under the tab clamp on the housing. |  Connect the rubber hose to the hard line through the tab. |  Install the locking clip to secure the rubber hose end to the tab. |
 Check all fittings and hardware, then properly bleed the brakes to insure maximum performance. The CPP Big Brake kit is designed to be used with 17-inch or larger wheels. | | |
