GM 15712801
Rotor

To replace the rear Brake Disc, collect the following tools: slide hammer with adapter (J 2619-01) and disc resurfacing kit (J 41013), wheel hub resurfacing kit (J 42450-A); disc removal tool (J-46277). Start by depowering the park brake and checking the Brake Master Cylinder reservoir fluid level should be in the middle point between the most upper and most lower limits. Mark the disc's relationship to the hub, take off the tire and wheel assembly. Use a large c-clamp so you can compress the brake caliper pistons then remove the Brake Caliper Bracket and the brake caliper and bracket as an assembly to support the caliper as part of the brake caliper without disconnecting the Hydraulic Hose. If it applies, remove Brake Disc retaining push nuts, and if it is required, apply a deadblow hammer to split the disc from the hub. In case the disc cannot be disassembled, assemble the disc removal tool (J-46277) and attach it to the slide hammer with adapter (J 2619-01) and push the tool between the disc friction surfaces to facilitate its removal. Examine the park brake parts for any damage, and replace damaged ones if necessary. Clean the hub/axle flange and Brake Disc mating surfaces with the aid of the wheel hub resurfacing kit (J 42450-A) and disc resurfacing kit (J 41013) to remove rust and contaminants. Line up and mount the disc and check the assembled lateral runout (LRO) for best brake performance. Forward any deviation in specifications of the lro to be corrected. Install the caliper and the caliper bracket, keeping in mind to clean the bolting threads and apply threadlocker gm p/n 12345493 (Canadian P/N 10953488) while tightening the caliper bracket bolts to 200 nm (148 ft. Lbs.). Finally, replace the tire and wheel assembly and pedal the brake pedal slowly to seat the caliper pistons and pads before topping off the master cylinder reservoir with clean brake fluid if needed.

You need to release the parking brake then take out two-thirds of the brake fluid from the master cylinder before replacing the rear Brake Disc. Lift the vehicle before dismounting the tire and wheel unit. Use wire to suspend the caliper and mounting bracket assembly as one unit from the suspension after you disconnect its bolts. Untwist the disc slowly while pulling it away from the axle center. Clean both sides of the wheel and axle hub before inserting the disc and twisting it into place toward the axle. Mount back the Steering Knuckle assembly with the caliper and its holder. Clear away existing adhesive from the bolt threads before putting on new caliper mounting bracket bolts. Brush threads with brake parts cleaner until dry and let them dry naturally. Cover the bolt threads with gm threadlocker p/n 12345493 or red loctite product #272. Fasten the caliper mounting bracket bolts to the Steering Knuckle unit and torque them at 175 n.m (129 lb ft) for 15 series models while achieving 300 n.m (221 lb ft) for 25 series vehicles. Complete the process by installing the tire and wheel components, then take away the safety stands and lower the vehicle.

To adjust the collected lateral runout (LRO) of the Brake Disc, initially ensure that an examination is done on the Brake Disc thickness, as whenever exceeded, brake pulsation is ensured. Start the measuring process by removing the conical Brake Disc washers (J 45101-100) and the lug nuts that were inserted at the time of the lro measurement. Check the mating surface of hub/axle flange and Brake Disc for any foreign particles or debris. Next, index the Brake Disc in another orientation to the resultant hub/axle flange, hold it in position and install one (1) conical Brake Disc washer (J 45101-100) and one (1) lug nut to the upper-most wheel stud, tightening the lug nut firmly by hand. Continue to retain the disc and install the balance conical Brake Disc washers (J 45101-100) and lug nuts to the brake studs with moderate hand tightening in a star shape. With the torque-limiting socket set (J 39544-KIT), torque the lug nuts in a star fashion to specification to correctly fasten the disc. Yes, take the lro that has been assembled and measure it and compare to the original prior to cleaning while keeping in mind that we have to take repeated measurements and hold it at a perpendicular alignment to obtain accurate reading. If measurement is within specifications, install the brake caliper and operate the brake pedal several times to lock the disc before installing the conical Brake Disc washers (J 45101-100) and lug nuts. When the measurement is outside specification, repeat the indexing and tightening until the best assembled lro measurement is achieved, and matchmark the final position of the disc to the wheel studs, if the orientation is differing from the original.

Begin the front Brake Disc replacement process by having the rotor resurfacing kit (J 41013) and wheel hub resurfacing kit (J 42450-A). First check the brake master cylinder fluid level and drain fluid until the mark reaches the middle point. Take off the wheel and tire unit to record how the disc sits against the hub. Place two big c-clamps on the brake caliper pistons to compress them before taking out the caliper bracket bolts. Keep the caliper assembly supported below the hydraulic brake hose rather than disconnecting it. Detach the Brake Disc retaining parts from inside the wheel if necessary while putting a deadblow hammer to separate the hub or disc from each other. Remove all rust and debris from the hub/axle flange and Brake Disc contact surfaces using j 42450-a wheel hub resurfacing kit and j 41013 rotor resurfacing kit. Rephrase verbalization when possible. Check if the disc removal with jack screw method made nicks on the hub flange while inspecting the mating areas. At last place the disc over the hub and fasten it using the Brake Disc screw until the torque reaches 12nm (106 inch lbs.). The assembled lateral runout measurement of the disc should be taken, and adjustments should be made when needed. Reinstall the caliper and bracket together while applying threadlocker gm 12345493 to the bolts and tightening them to 180 nm (133 ft.lbs.). Put the tire wheel assembly back in place after lowering the vehicle and apply the brake pedal slowly with the engine stopped. Adjust caliper pistons and pads by topping up clean brake fluid when needed.

To overhaul the front Brake Disc of 1500 series vehicles you need a disc resurfacing kit (J 41013) and wheel hub resurfacing kit (J 42450-A). Start by observing the brake master cylinder reservoir fluid level. Drain fluid when the level exceeds halfway so it reaches that mark. Take the tire and wheel off then make disc position marks before squeezing the brake caliper pistons together with two large c-clamps. You should take off the Brake Caliper Bracket bolts and assemble caliper and bracket together while keeping the hydraulic brake flexible hose intact. Hit hub or disc surface with a deadblow hammer until Brake Disc screw and push nuts release from their positions. Use the j 42450-a fluid to clean the hub/axle flange surface and j 41013 fluid to clean the inside of the Brake Disc. Set the Brake Disc in its correct position before installing it and fastening the Brake Disc screw to 12 nm (106 inch lbs). When the brake system needed repairs you should measure lro after installation and take corrective action if the value does not meet industry standards. Secure the new caliper using threadlocker gm 12345493 as directed while tightening each caliper bracket bolt to 180 nm. After reattaching the tire and wheel assembly you must lower the vehicle while actively working the brake pedal to let the caliper pistons and pads find their proper placement before adding clean brake fluid to the reservoir as needed.

The brake disc repair needs Disc Resurfacing Kit J 41013 plus Wheel Hub Resurfacing Kit J 42450-A. The routine brake system service does not include disc brake disc refinishing and technicians should refrain from refurbishing new discs to handle brake system noise issues or other brake-system-related problems. The discs need evaluation for thickness before any refinishing work to confirm they stay above the specified minimum. You need to refinish the brake discs when you detect gross variations in surface thickness plus severe rust spots, breakage, hot spots, blue-colored spots, and scoring beyond set specifications. Clean both surfaces of the disc and hub using Wheel Hub and Disc Resurfacing Kits to prepare the assembly for separation. Put the brake disc on the lathe correctly and check the mating surface for dirt particles before following the manufacturer's instructions for brake disc attachment. Check the mounting position by letting the lathe run against disc friction surfaces until the cutting tools touch. Then verify proper alignment from the witness mark. Before the disc refinishing process continue follow the manufacturer's lathe instructions and check discs thickness during all cuts. The brake disc must be replaced when refinishing does not lower its thickness below the defined limit. Follow directed speed settings as you sand with non-directional tool using 120 grit aluminum oxide or create a flat surface with 150 grit aluminum oxide sandpaper when the tool lacks non-directionality. After cleaning friction areas you need to measure the assembled LRO to check if it matches disc brake standards properly. Regular maintenance also includes minor adjustments without exceeding manufacturing specifications.

Release the park brake and raise the vehicle securely.

Measure the assembled Lateral Runout (LRO) and correct it if necessary.

Inspect the mating surfaces for debris.

Measure the assembled LRO of the brake rotor and compare this measurement to the original; if it is within specifications, proceed to install the brake caliper and depress the brake pedal several times to secure the rotor in place before removing the conical brake rotor washers (J 45101-100) and lug nuts.

Tighten them to 200 Nm (148 lb ft).

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

Ensure no debris remains.

Tighten to 200 N.m (148 lb ft) for JH5 vehicles or 300 N.m (221 lb ft) for JH6/JH7 vehicles.

Tap around the perimeter of the hub extension with a rubber mallet.

Measure the assembled lateral runout to ensure optimal performance and correct it if necessary.

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

Tap around the perimeter of the hub extension with a non-metallic mallet to loosen it.

Align the hub and rotor if applicable, then install each new wheel stud by inserting the stud, adding 4 washers, and securing a lug nut with the flat side facing the washers.

As an assembly without disconnecting the hydraulic brake flexible hose.

Bring in the cutting tools to contact the rotor friction surfaces and check the witness mark to confirm proper mounting.

First, release the park brake if necessary and remove the tire and wheel assembly.

Utilize the Hub Cleaning Kit (J 42450-A) to clean the wheel bearing and hub, ensuring any rust or foreign material is removed from the mating surface.

Begin by checking the brake rotor thickness variation, as exceeding the maximum acceptable level can lead to brake pulsation.

Inspect for foreign particles and ensure the hub flange is free of nicks.

Remove the caliper and mounting bracket as an assembly.

Inspect the thickness and replace the rotor if it exceeds the minimum allowable thickness.

Release the parking brake and inspect the brake master cylinder reservoir fluid level.

Tighten the lug nut to draw the stud into the assembly, ensuring the hub is tight against the rotor and the stud is fully seated.

Thickness variation may develop in the brake rotor over time, typically between 4,800-11,300 km (3,000-7,000 mi).

Align the hub and rotor if applicable.

Remove the tire and wheel assembly, then mark the rotor's relationship to the hub.

Inspect the thickness after each cut.

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

Remove the hub and rotor assembly, marking the relationship between the hub and rotor.

Reinstall the park brake shoe and axle shaft, then adjust the park brake shoe.