GM 19174917 Front Brake Rotor Assembly

Before replacing the brake components, the vehicle has to be lifted and properly supported it is then necessary to also remove the wheel and tire assembly. Subsequently, unbolt the brake caliper from the axle and then using a wire fix the brake caliper on the coil spring but not to the brake hose. On the 1990-91 Eldorado and Seville models, the caliper mounting bracket must be unbolted from its position to be removed. If present, then simply remove the retainers from the wheel studs since the retainers do not come back on. Completely disassemble the disc brake rotor and analyze the situation, then turn to machining or replacement of it. For the installation, position of the disc brake rotor over the wheel studs and hub assembly, further for the 1990-91 Eldorado and Seville models use the new bolts to attach the caliper mounting bracket and tighten to 83 ft lbs. (112 Nm). Reinstall the brake caliper and after that the wheel and tire assembly, and then the vehicle should be lowered again. While inspecting, observe whether the rotor surface is shiny due to overheating, or glazed, or scored; machining of discoloration or glazed rotor is required, whereas light score up to 0.050 inch is allowed. (1.2mm) is typically acceptable. Check rotor thickness at at least four points in the circumference and any variation greater than o.0005 inch indicated by a dial indicator can cause brake pedal pulsation. (0.013mm) necessitates machining. Further, check for too much side play as this is probable to make the vehicle shake upon application of brakes. Run out in the lateral direction can be tested again by re fastening rotor with wheel lug nuts, placing dial indicator on the steering knuckle or caliper mounting bracket then making total indicated run out when the rotor has revolved once fully. In the case of large runout the shaft could be indexed on the rotor on the hub to correct the condition. Otherwise check the hub and bearing assembly for excessive lateral runout or looseness and replace it and again check the rotor. If the rotor still stays over the specifications, then machine it but it must not go below the minimum standards.

Before replacing the brake components, the vehicle has to be lifted and properly supported it is then necessary to also remove the wheel and tire assembly. Subsequently, unbolt the brake caliper from the axle and then using a wire fix the brake caliper on the coil spring but not to the brake hose. On the 1990-91 Eldorado and Seville models, the caliper mounting bracket must be unbolted from its position to be removed. If present, then simply remove the retainers from the wheel studs since the retainers do not come back on. Completely disassemble the disc brake rotor and analyze the situation, then turn to machining or replacement of it. For the installation, position of the disc brake rotor over the wheel studs and hub assembly, further for the 1990-91 Eldorado and Seville models use the new bolts to attach the caliper mounting bracket and tighten to 83 ft lbs. (112 Nm). Reinstall the brake caliper and after that the wheel and tire assembly, and then the vehicle should be lowered again. While inspecting, observe whether the rotor surface is shiny due to overheating, or glazed, or scored; machining of discoloration or glazed rotor is required, whereas light score up to 0.050 inch is allowed. (1.2mm) is typically acceptable. Check rotor thickness at at least four points in the circumference and any variation greater than o.0005 inch indicated by a dial indicator can cause brake pedal pulsation. (0.013mm) necessitates machining. Further, check for too much side play as this is probable to make the vehicle shake upon application of brakes. Run out in the lateral direction can be tested again by re fastening rotor with wheel lug nuts, placing dial indicator on the steering knuckle or caliper mounting bracket then making total indicated run out when the rotor has revolved once fully. In the case of large runout the shaft could be indexed on the rotor on the hub to correct the condition. Otherwise check the hub and bearing assembly for excessive lateral runout or looseness and replace it and again check the rotor. If the rotor still stays over the specifications, then machine it but it must not go below the minimum standards.

Attach the caliper mounting bracket using new mounting bolts, tightening them to 83 ft. lbs. (112 Nm).

Next, detach the brake caliper and suspend it with wire from the strut, ensuring it does not hang from the brake hose.