Parking Brake Issues (most likely culprits given your repair):
* Cable Adjustment: The most common reason for a weak parking brake is improperly adjusted cables. Replacing the calipers and pads doesn't automatically fix cable issues. The cables themselves might be stretched, frayed, or seized. They need to be adjusted to ensure the correct amount of tension on the brake shoes/calipers. This often involves accessing adjustment points near the lever and at the caliper/brake mechanism itself. Consult your vehicle's repair manual for the correct procedure; improper adjustment can lead to further problems.
* Parking Brake Shoes (if drum brakes): If your MX-3 has rear drum brakes (common for that year), the parking brake uses separate shoes inside the drum. These shoes could be worn, glazed, or rusty. Even with new caliper pads (for the service brake), the parking brake shoes may be the problem. They might need replacement or cleaning and adjustment.
* Cable Routing and Obstructions: Check for any kinks, bends, or damage to the parking brake cables. Ensure they're properly routed and not obstructed by anything. A seized section can significantly reduce effectiveness.
* Rear Drum Condition (if applicable): If you have rear drum brakes, the drums themselves could be rusted or scored, preventing the shoes from contacting the drum surface properly. They may need machining or replacement.
* Calipers (even if new): While you're replacing the parking brake caliper, ensure that the new one is correctly installed and functions smoothly. A faulty new part isn't unheard of. Double-check that the piston is retracting correctly.
* Parking Brake Lever/Actuator: In some cases, the parking brake lever mechanism itself could be worn or damaged, preventing it from applying sufficient force to the cables.
Service Brake Issues (less likely given parking brake focus but still possible):
* Brake Fluid: Low or contaminated brake fluid will significantly reduce braking efficiency. Have your fluid flushed and replaced, especially since it's an older car.
* Brake Lines: Corroded or damaged brake lines can restrict fluid flow. Inspect them for rust, leaks, or kinks.
* Master Cylinder: While less common, a failing master cylinder can affect both service and parking brakes.
* Wheel Cylinders (rear): If you have rear drum brakes, the wheel cylinders could be leaking or seizing.
Troubleshooting Steps:
1. Consult a Repair Manual: A factory service manual for your 1991 Mazda MX-3 is invaluable. It will provide detailed instructions on adjusting the parking brake cables and troubleshooting brake systems.
2. Adjust Parking Brake Cables: This is the most likely first step. Follow the instructions in your repair manual carefully.
3. Inspect Parking Brake Shoes (if applicable): If you have drum brakes, remove the drums and check the condition of the parking brake shoes.
4. Check Brake Fluid Level and Condition: Ensure the fluid is clean and at the correct level. A flush and bleed is recommended.
5. Inspect Brake Lines and Hoses: Check for any damage, leaks, or corrosion.
6. Visual Inspection of Calipers: Make sure the new caliper is correctly fitted and moving freely.
7. Professional Inspection: If you're uncomfortable working on your brakes, take it to a qualified mechanic. Brake systems are crucial for safety, and it's better to be safe than sorry.
Remember, if you're unsure about any step, it's best to seek professional help. Working on brakes requires specific knowledge and tools to ensure safety and proper function.
