I. Safety First:
* Jack Stands: Never work under a car supported only by a jack. Use jack stands rated for the weight of your vehicle.
* Wheel Chocks: Place wheel chocks behind the wheels that remain on the ground.
* Gloves: Protect your hands.
* Safety Glasses: Protect your eyes from flying debris.
* Work Area: Choose a clean, well-lit, and level surface.
II. Tools You'll Need:
* Jack and jack stands
* Wheel chocks
* Lug wrench
* Socket wrench set (metric) with extensions and ratchet
* Torque wrench (essential for proper tightening)
* Brake caliper piston compressor tool (C-clamp can work in a pinch, but a dedicated tool is safer and easier)
* Wire brush
* Brake cleaner
* Anti-seize lubricant
* New brake pads
* New rotors
* Penetrating oil (like PB Blaster)
III. Steps:
A. Preparation:
1. Park on a level surface, engage the parking brake, and chock the wheels.
2. Locate the owner's manual for torque specifications for lug nuts, caliper bolts, etc. This is crucial to avoid damage.
B. Removing the Wheel:
1. Loosen the lug nuts slightly with the lug wrench before jacking up the car. This is much easier before the wheel is off the ground.
2. Safely jack up the vehicle and secure it with jack stands.
3. Remove the lug nuts completely and carefully remove the wheel.
C. Removing the Caliper and Brake Pads:
1. Locate the caliper mounting bolts. These are usually on the back of the caliper.
2. Spray penetrating oil on the bolts if they are stubborn.
3. Carefully remove the caliper bolts and gently remove the caliper assembly. It might be helpful to support the caliper with a bungee cord or wire to prevent it from hanging by the brake line.
4. Remove the brake pads. They typically just slide out. Note their orientation for proper reinstallation.
5. Compress the caliper piston. Use the piston compressor tool to push the piston back into the caliper. This creates space for the new, thicker pads. If using a C-clamp, be very careful not to damage the piston or seal.
D. Removing and Replacing the Rotor:
1. Remove the rotor. Some rotors are held in place by only the caliper, while others might have mounting bolts. If there are mounting bolts, remove them. The rotor should then slide off the hub.
2. Clean the hub with a wire brush to remove any rust or debris.
3. Install the new rotor. Make sure it's seated properly on the hub.
E. Reassembly:
1. Install the new brake pads. Make sure they are properly seated in the caliper.
2. Reinstall the caliper assembly, making sure the brake pads are properly positioned against the rotor.
3. Tighten the caliper mounting bolts to the manufacturer's specified torque.
4. Reinstall the wheel and tighten the lug nuts to the manufacturer's specified torque in a star pattern (opposite nuts, then the ones in between). Do not overtighten!
5. Lower the vehicle and remove the jack stands.
6. Tighten the lug nuts again after lowering the vehicle to ensure they are properly seated.
7. Repeat steps B-E for the other wheel.
F. Post-Installation:
1. Pump the brake pedal several times to build up pressure in the system.
2. Check for leaks around the caliper and brake lines.
3. Test drive the vehicle to ensure the brakes are working correctly. If you feel any unusual vibrations or noises, have a mechanic inspect the brakes immediately.
Important Considerations:
* Bleeding the brakes: In most cases, you shouldn't need to bleed the brakes after replacing pads and rotors, but it is always a good idea to check your owner's manual. If you're uncomfortable, a mechanic can do it for you.
* Rotor thickness: Check the minimum thickness specification for your rotors. If the old rotors are too thin, they need replacement regardless of condition.
* Brake fluid: While unlikely to require replacement after just pads and rotors, topping off your brake fluid is often a good idea before the next service.
This information is for guidance only. Consult your vehicle's service manual for detailed instructions and torque specifications specific to your 2004 Pontiac Grand Prix. Incorrect installation can lead to brake failure, resulting in serious injury or death. If you are unsure about any part of this process, seek professional help.
