1. Diagnosis:
* Feel the Throbbing: Is the throbbing most noticeable when braking at higher speeds? This strongly points to warped rotors. If it's a constant vibration regardless of speed, it could be other issues (like a wheel bearing problem, unbalanced tires, or something wrong with the suspension).
* Visual Inspection: Carefully examine the rotors. Look for any obvious warping, scoring, or excessive rust. A warped rotor will often have a noticeable uneven surface.
* Feel the Rotors: If possible and safe, feel the rotors (after they have cooled down completely). You might be able to feel unevenness on their surfaces.
* Check for other issues: Inspect the brake pads for wear; worn pads might contribute to uneven braking. Check the brake calipers for sticking or binding. Check for any play in wheel bearings.
2. Fixing the Problem:
The most likely solution is replacing the warped rotors. Here's what you'll need and the process:
Tools and Materials:
* New Brake Rotors (2): Get rotors specifically designed for your 1993 Cadillac DeVille. Ensure they are the correct size and specifications.
* New Brake Pads (2 sets): Always replace brake pads when changing rotors. Using old pads with new rotors is a recipe for uneven wear and potentially damaging the new rotors.
* Jack and Jack Stands: Essential for safely lifting the vehicle.
* Lug Wrench: To remove the wheels.
* Wheel Chocks: For added safety.
* Caliper Compression Tool: To compress the brake caliper pistons.
* Socket Set and Wrenches: The specific sizes will depend on your vehicle, consult your repair manual.
* Brake Cleaner: To clean brake components.
* Gloves: To protect your hands.
* Repair Manual (Highly Recommended): A repair manual specific to your 1993 Cadillac DeVille will provide detailed instructions and torque specifications.
Procedure:
1. Safety First: Park on a level surface, engage the parking brake, and use wheel chocks.
2. Lift the Vehicle: Use the jack and jack stands to safely lift the vehicle. Securely support it on the jack stands.
3. Remove the Wheels: Remove the lug nuts and carefully remove the wheels.
4. Compress the Caliper Pistons: Using the caliper compression tool, carefully compress the caliper pistons to allow space for the new, thicker brake pads.
5. Remove the Old Brake Pads and Rotors: Remove the old brake pads and rotors.
6. Clean the Components: Thoroughly clean the caliper, mounting brackets, and hub using brake cleaner.
7. Install the New Rotors: Carefully install the new brake rotors.
8. Install the New Brake Pads: Install the new brake pads, ensuring they're correctly seated.
9. Reassemble: Reinstall the calipers, wheels, and lug nuts, tightening them to the manufacturer's specified torque. Consult your repair manual for the correct torque values.
10. Lower the Vehicle: Carefully lower the vehicle from the jack stands.
11. Test the Brakes: Test the brakes carefully, preferably in a safe, empty area. The throbbing should be gone. If not, there might be another issue.
Important Considerations:
* Bleeding the Brakes: If you've worked on the braking system, it's a good idea to bleed the brakes to remove any air that might have entered the system. This requires two people and a brake bleeder kit.
* Professional Help: If you're not comfortable working on your brakes, it's best to take your car to a qualified mechanic. Brake issues are critical for safety.
* Caliper Issues: If a caliper is sticking, it can cause uneven brake pad wear and warped rotors. Inspect the calipers closely; if they appear damaged or sticky, they may need to be replaced or rebuilt.
This information is for general guidance. Always consult your vehicle's repair manual for specific instructions and torque specifications for your 1993 Cadillac DeVille. Incorrectly performing brake repairs can be extremely dangerous.
