GM 19210603
Rotor, Front

To achieve optimal brake system performance our technician needs to smooth both braking parts before any brake disc work on a vehicle. Start on a quiet road and drive up to 48 km/hour (30 mph) for brake burnishing. Be cautious not to heat up your brakes throughout this operation. Lightly push the brakes until you stop the vehicle smoothly to prevent brake locks. Perform this brake acceleration and stopping pattern about 20 times keeping adequate cooling time between sessions to help pad and brake disc surface smoothing.

Before working on the Brake Disc, make sure that nothing on the caliper or caliper bracket can rotate with the rest of the system. Undo the conical disc washers (J 45101-100) and the lug nuts installed during the assembled lateral runout procedure. Check the surface where the hub/axle flange joins with the Brake Disc to make sure it is clean. Following the instructions from the manufacturer, set up the lathe and begin refinishing the Brake Disc, watching the thickness after every cut. The Brake Disc needs to be replaced if it is thinner than the minimum after you refinish it. After you have finished refinishing, use the proper speed setting to apply a non-directional finish on the disc; in case the lathe includes a non-directional finishing attachment, use 120 grit aluminum oxide sandpaper, or opt for a sanding block with 150 grit aluminum oxide sandpaper if it does not. Make sure to clean all sides of the Brake Disc's friction surfaces using denatured alcohol or a suitable brake cleaner. As soon as the lathe comes off the vehicle, use a ruler to see if the assembled lro of the disc is within limits. If the measurement goes over the maximum limit, more adjustments need to be done. If your lro measurement is acceptable after refinishing, attach the brake caliper before pressing the brake several times, and take off the disc washers along with the lug nuts.

The brake disc service needs these tools: Rotor Resurfacing Kit (J 41013) plus Wheel Hub Resurfacing Kit (J 42450-A). During typical brake system duties the disc brake discs keep their factory finish and new disc brake discs also do not need refinishing work. Regrooving should not solve brake system problems that include brake noise, unbalanced pad wear patterns, light surface corrosion, and less-than-maximum score depth when the disc has enough materials left. Refinishing process is needed only when the disc brake discs show excessive uneven thickness, rust, small holes, cracks, hot spots, extreme discoloration, or deep scores that exceed the accepted specifications. Use the Wheel Hub Resurfacing Kit (J 42450-A) and the Rotor Resurfacing Kit (J 41013) to clean rust and impurities before beginning disc and hub surface refinement. Look for foreign items on brake mating surfaces while you set the brake disc in place on the brake lathe. Check all equipment parts for cleanliness. As the lathe turns follow the cutting tool movement until it touches disc surfaces while looking for the knife mark to verify correct positioning. Guide the lathe manufacturer's steps to refinish the disc while tracking its thickness until the minimum limit is met and replace it when reached. Keep the finish even by using the recommended lathe speeds combined with non-directional tools and aluminum oxide sandpaper that is 120 grit or a sanding block with 150 grit sandpaper. After cleaning the brake surfaces use denatured alcohol or brake cleaner to take the disc off the lathe. Measure assembled LRO to improve disc brake performance and make adjustments if required.

Start Brake Disc jh5 replacement by checking the brake master cylinder reservoir fluid level. Drain fluid to the middle point if reservoir liquid is above that mark. Lift the vehicle moderately then take off the wheel and tire parts. Keep a reference point when reinstalling the original Brake Disc because it must align with the Wheel Hub properly. Put down 2 large c-clamps onto caliper housing and push them against disc housing to draw all brake pistons into their home position. Secure the brake caliper with mechanic wire to protect the hydraulic brake hose during maintenance. Securely suspend the brake caliper assembly by removing its 2 bolts then placing wire under it during the removal process. To access the wheel studs remove Brake Disc retaining push nuts if needed and separate the Brake Disc screw. First place wheel nuts on the studs then hit between the studs for a perfect disc removal with a deadblow hammer. After cleaning all surfaces apply penetrating oil then add two m10 x 1.5 bolts in disc's threaded holes with regular tightening to push the disc away. To install the part use the j-42450-a (Wheel Hub Resurfacing Kit) to clean rust from the hub flange and use j-41013 (Disc Resurfacing Kit) to clean the inner Brake Disc surface. Apply the disc to its original position while monitoring that no particles reach the surfaces and install it. Secure the Brake Disc screw at 12 nm (106 lb in), put in the brake caliper and bracket. Prepare the mounting bolt threads by clearing away residual adhesive then using brake parts cleaner to clean the threads. Finish the preparation by applying threadlocker gm p/n 12345493 (Canadian P/N 10953488) onto the threads. Put on the two mounting bolts and secure them to 175 nm torque value. Put back the tire and wheel components before gently pushing the brake pedal to its middle range through several activation cycles until a solid braking effect exists. Add fresh brake fluid to the reservoir until it reaches the correct mark. The braking system needs to be run in with new brake pads against refreshed or new discs.

Align and install the rotor, then measure the assembled lateral runout (LRO) to ensure optimal performance.

Raise and support the vehicle, then remove the tire and wheel assembly.

Lower the vehicle and properly seat the brake caliper pistons by applying and releasing the brake pedal several times before filling the master cylinder reservoir with clean brake fluid.

Clean the area, apply penetrating oil, and use two M10 x 1.5 bolts to force the rotor from the hub.

Release the park brake and raise the vehicle securely.

Align the rotor to its original position on the hub and install it, followed by the caliper and caliper mounting bracket assembly.

Inspect the mating surface of the hub/axle flange and the brake rotor for any foreign particles or debris.

Fill it with clean brake fluid.

Clean the surfaces, apply penetrating oil, and use two M10 x 1.5 bolts to force the rotor off.

Mark the rotor's relationship to the hub.

First, raise and support the vehicle, then remove the tire and wheel assembly.

Clean the hub flange mating surfaces with the wheel hub resurfacing kit (J 42450-A) and the rotor resurfacing kit (J 41013).

Ensure the mating surfaces are free of debris, align the rotor to its original position, and install it.

Inspect the mating surfaces for debris.

Fill the master cylinder reservoir to the proper level with clean brake fluid.

Slide Hammer With Adapter (J 2619-01), Rotor Resurfacing Kit (J 41013), Wheel Hub Resurfacing Kit (J 42450-A), and Rotor Removal Tool (J-46277).

Clean the braking surfaces with GM P/N 12377981 or an equivalent brake parts cleaner.

Install the park brake shoe and wheel bearing, adjusting the park brake shoe as needed.

Remove 2/3 of the brake fluid from the master cylinder.

Inspect the mounting surface of the hub/axle flange and the brake rotor for any foreign particles or debris.

Apply Threadlocker GM P/N 12345493 or Red LOCTITE (TM) #272 to the threads of the bolt.

Ensure the rotor has adequate thickness to remain above the minimum allowable specification after refinishing.

Tighten the lug nut to draw the stud into the hub and rotor assembly, ensuring the hub is tight against the rotor and the stud is sealed correctly before removing the lug nut and washers.

Lower the vehicle and properly seat the brake caliper pistons and pads by applying and releasing the brake pedal several times before filling the master cylinder reservoir with clean brake fluid.

Do the same as for the 15 series, which is to take out the splash shield.

Use the J 42450-A Wheel Hub Resurfacing Kit and the J 41013 Rotor Resurfacing Kit.

Remove the tire and wheel assembly.

Remove the rear axle shaft and hub, noting that the bearings and cups do not need to be removed unless replacement is required.

Mark the relationship between the hub and rotor before removing them.

Rotor Resurfacing Kit (J 41013) and Wheel Hub Resurfacing Kit (J 42450-A).

Clean the friction surfaces with denatured alcohol or an approved brake cleaner, remove the rotor from the lathe, and measure the assembled LRO to ensure optimal disc brake performance, adjusting if it exceeds specifications.

Clean the bolt threads, apply Threadlocker GM P/N 12345493 (Canadian P/N 10953488), and tighten the caliper bracket bolts to 180 Nm (133 ft. lbs.).

To achieve a firm pedal, ensuring the brake caliper pistons and brake pads are properly seated.

Tighten the nut to 3.5 Nm (31 inch lbs.).

Rotor Resurfacing Kit (J41013) and Wheel Hub Resurfacing Kit (J42450-A).

Release the park brake and raise the vehicle for support.

Remove any rotor retaining push nuts from the wheel studs.

Exceeding the maximum acceptable level can lead to brake pulsation.

Release the park brake and raise and support the vehicle.