1. Safety First!
* Engage the parking brake firmly.
* Raise the vehicle securely using jack stands placed on appropriate jack points (consult your repair manual). Never work under a vehicle supported only by a jack.
* Block the front wheels.
* Wear safety glasses and gloves.
2. Diagnosis:
Before you start replacing parts, determine *why* the brakes aren't working correctly. Common issues include:
* Low brake fluid: Check the brake fluid reservoir. Low fluid indicates a leak somewhere in the system.
* Worn brake pads: Inspect the brake pads for wear. Replace if they are worn below the minimum thickness (check your repair manual).
* Worn rotors: Inspect the rotors for scoring, grooves, or excessive wear. Resurfacing might be possible, but often replacement is necessary.
* Sticking caliper: Check for caliper piston sticking or binding. This often causes uneven brake pad wear.
* Leaking caliper: Inspect the caliper for leaks. A leaking caliper needs replacement.
* Brake lines or hoses: Check for leaks, kinks, or damage in the brake lines and hoses leading to the rear calipers.
3. Repair Procedures (assuming worn pads and rotors as the problem):
This outlines a general procedure. Refer to your repair manual for specifics.
* Remove the wheel: Use a lug wrench to remove the wheel nuts and take off the wheel.
* Remove the caliper: Usually, you'll need to compress the caliper piston (using a C-clamp and a block of wood to avoid damaging the piston) to create space for the new brake pads. Some calipers have a bleed screw that helps with piston retraction. Once compressed, carefully remove the caliper and hang it securely using a wire or bungee cord to prevent stressing the brake line.
* Remove the brake pads: Carefully remove the old brake pads.
* Inspect and replace the rotors: If the rotors are scored, grooved, or excessively worn, replace them. Clean the rotor mounting surface on the hub.
* Install new brake pads: Insert the new brake pads into the caliper bracket.
* Install the caliper: Carefully mount the caliper back onto the bracket.
* Bleed the brakes: After reinstalling the caliper, you'll need to bleed the brakes to remove any air that might have entered the system during the repair. This is crucial for proper brake function. Use a brake bleeding kit and follow the proper bleeding procedure (consult your repair manual). This usually involves opening the bleeder valve on the caliper while an assistant pumps the brake pedal.
* Reinstall the wheel: Tighten the lug nuts in a star pattern to ensure even pressure.
* Lower the vehicle: Carefully lower the vehicle to the ground.
* Test the brakes: Test the brakes thoroughly in a safe area before driving the vehicle on the road. If the brake pedal feels spongy or the brakes are ineffective, there's likely still air in the system, or another problem.
Important Considerations:
* Repair Manual: A repair manual specific to your 1993 Pontiac Grand Prix is essential for accurate instructions and torque specifications.
* Tools: You'll need various tools, including a jack, jack stands, lug wrench, socket set, C-clamp, brake caliper tool, brake bleeding kit, and possibly a rotor turning tool.
* Parts: Order the correct brake pads and rotors for your vehicle. Ensure they are from a reputable supplier.
* Brake Fluid: Use the correct type of brake fluid specified in your owner's manual.
This information is for guidance only. Improper brake repair can be extremely dangerous. If you are not comfortable performing this repair, take your vehicle to a qualified mechanic.
