GM 22968231
Rotor, Rear

You should start by lowering the parking brake and checking brake fluid in the reservoir of a 2500 series vehicle. Only perform this step when the fluid level is set below the center mark between top and bottom indicators. After lifting the vehicle put it on stands you need to take out the tire and wheel unit while noting the disc's positioning relative to the hub. Press a large c-clamp firmly on top of the caliper housing to push in the brake caliper pistons until the piston stays fully pushed back. Remove the clamp after that. Use strong mechanic wire to hold up the brake caliper to safeguard the flexible hydraulic brake hose against damage when working above it. Work the caliper unit as one piece by cutting off the bracket bolts and moving the assembly from its location without changing the hydraulic hose. With proper clearance remove the Brake Disc retaining nuts connected to wheel studs. If needed strike the hub end with deadblow hammer to detach disc from hub before pulling off the disc from its position. Remove all rust and other materials from the hub/axle contact zone and Brake Disc installation area before working with the wheel hub resurfacing kit j-42450-a and disc resurfacing kit j-41013. Verify that mating surfaces are without debris after setting the disc at its proper location and threading it in direction of the axle. Reassemble the brake caliper system after placement but clean Brake Caliper Bracket bolt threads with brake parts cleaner and apply threadlocker gm p/n 12345493 (Canadian P/N 10953488) prior to tightening bolts to a torque of 200 nm (148 lb ft). Put the wheel back onto the tire while keeping the engine turned off then apply the brake pedal one-third of full stroke several times until you feel a firm pedal feel that correctly seats the caliper pistons into place. Add clean brake fluid to reach the recommended level in the master cylinder while fixing the brake system by running the pads and disc against each other.

Before replacing the rear Brake Disc on a 1500 series vehicle check the brake master cylinder reservoir fluid level; you must lower it to the midpoint between the maximum-full and minimum marks when the current level is above that point. You can drive the vehicle only if necessary before hoisting it up. Position a large c-clamp over the caliper housing against its back plate to push the caliper piston into its bore until complete retraction. Use mechanic wire to support the brake caliper when you extract the assembly together with the brake bracket to stop damaging the hydraulic flexible brake hose during service. When keeping the original Brake Disc mark its position on the hub before adjusting park brake function and taking off push nuts from disc parts. Soak wheel studs in penetrating oil then fasten lungs nuts onto them. Use a dead blow hammer to tap the disc until it loosens before you take off all lug nuts and the disc from the axle flange. Apply wheel hub and disc resurfacing tools j-42450-a and j-41013 to remove all rust and particles from hub/axle flange and Brake Disc contacting surfaces. Put the disc in place and fix back the caliper and its bracket. Take out the factory adhesive from threads and clean them using denatured alcohol before installing Brake Caliper Bracket mounting bolts. Apply threadlocker gm p/n 12345493 (Canadian P/N 10953488). Fasten the bolts to 165 nm, check the parking brake action, and place the tire with the wheel back on position. After turning off the engine press the Brake Pedal about two-thirds of its distance and let it go remembering these steps until you find the firm pedal linkage to position the caliper pistons and pads correctly. After filling the master cylinder to match the fluid necessities, brush the new disc surface against the pads to increase the braking effect.

Measure the assembled lateral runout (LRO) to ensure it meets specifications.

Use the Wheel Hub Resurfacing Kit (J 42450-A) for the hub flange and the Rotor Resurfacing Kit (J 41013) for the inside diameter of the brake rotor.

Release the park brake and inspect the fluid level in the brake master cylinder reservoir, ensuring it is not above the midway point between the maximum and minimum levels; if it is, remove fluid to reach that point.

Support the brake caliper with heavy mechanic wire to prevent damage to the hydraulic flexible brake hose.

Inspect the fluid level in the brake master cylinder reservoir; if the level is above midway, remove fluid to that point.

Align the hub and rotor for installation, insert each new wheel stud into the hub and rotor assembly, add 4 washers, and secure a lug nut with the flat side toward the washers.

Ensure the stud is fully seated.

Lower the vehicle, and with the engine off, gradually apply the brake pedal to about 2/3 of its travel, then release it. Repeat this process until a firm pedal is achieved.

Reinstall the caliper and caliper bracket assembly, ensuring to clean the threads of the mounting bolts and apply threadlocker GM P/N 12345493 (Canadian P/N 10953488) before tightening the bolts to 165 Nm (122 lb ft).

Inspect the brake master cylinder reservoir fluid level; if it is above the midway point, remove fluid to that level.

Support the brake caliper with heavy mechanic wire.

Remove the 2 mounting bolts and take out the brake caliper and bracket as a single unit, then support the assembly with the wire.