How To Replace Back Brakes?

Replacing your back brakes is a common maintenance task that can save you money compared to taking your vehicle to a mechanic. While it might seem daunting, with the right tools, information, and a little patience, you can successfully complete this job yourself. This guide provides a comprehensive step-by-step walkthrough to help you confidently replace your back brakes.

Back brakes are a crucial safety component of your vehicle. Worn or damaged brakes can significantly reduce your stopping power, increasing the risk of accidents. Recognizing the signs of brake wear and understanding the replacement process empowers you to maintain your vehicle's safety and performance.

Detailed Explanations

Tools & Materials:

Replacing back brakes requires a specific set of tools and materials to ensure the job is done safely and correctly. Essential tools include a jack and jack stands for lifting and supporting the vehicle, a lug wrench to remove the wheels, a socket set and wrenches for removing bolts, a brake caliper tool (especially for rear brakes with integrated parking brakes), a C-clamp (may be needed for some calipers), brake cleaner, brake grease, new brake pads, new brake rotors (if necessary), gloves, safety glasses, and a torque wrench. You may also need penetrating oil for stubborn bolts and a wire brush for cleaning.

Safety Precautions:

Safety is paramount when working on your vehicle's brakes. Always wear safety glasses to protect your eyes from debris and brake cleaner spray. Wear gloves to protect your hands from dirt, grease, and brake fluid, which is corrosive. Never work under a vehicle supported only by a jack; always use jack stands placed on a solid, level surface. Chock the front wheels to prevent the vehicle from rolling. Work in a well-ventilated area, especially when using brake cleaner. Dispose of old brake pads and fluid properly, as they can be hazardous to the environment.

Preparation:

Proper preparation is key to a smooth and efficient brake replacement. Park your vehicle on a level surface and engage the parking brake (unless the rear brakes are completely inoperable, in which case, chock the front wheels). Gather all your tools and materials in a convenient location. Loosen the lug nuts on the rear wheels before jacking up the vehicle. Disconnect the negative battery terminal to prevent any accidental electrical shorts. This is particularly important if your vehicle has electronic parking brake functionality. Consult your vehicle's repair manual for any specific warnings or procedures related to disconnecting the battery.

Removal of Old Brakes:

1. Loosen Lug Nuts: Use a lug wrench to loosen the lug nuts on the wheel you'll be working on. Do this before you lift the vehicle.
2. Jack Up Vehicle: Position the jack under the vehicle's frame near the rear wheel. Consult your owner's manual for the correct jacking points.
3. Secure with Jack Stands: Once the wheel is off the ground, place jack stands under the vehicle's frame for support. Never work under a vehicle supported only by a jack.
4. Remove Wheel: Finish unscrewing the lug nuts and remove the wheel.
5. Locate Caliper Bolts: Identify the bolts that hold the brake caliper in place. These are typically located on the back of the caliper.
6. Remove Caliper Bolts: Use a wrench or socket to remove the caliper bolts. You may need to use penetrating oil if they are rusted or stuck.
7. Remove Caliper: Carefully slide the caliper off the brake rotor. If it's stuck, gently pry it off with a screwdriver or pry bar. Be careful not to damage the brake lines. Support the caliper with a wire or bungee cord to prevent it from hanging by the brake hose.
8. Remove Brake Pads: Remove the old brake pads from the caliper bracket. Note their orientation for reassembly.
9. Remove Caliper Bracket (if necessary): Some vehicles require removing the caliper bracket to remove the rotor. If so, remove the bolts holding the bracket in place.
10. Remove Rotor: If the rotor is easily removed, simply slide it off the hub. If it's stuck, use a rubber mallet to gently tap it from behind. You may need to use penetrating oil and tap around the rotor's center hole.

Inspection & Cleaning:

After removing the old brakes, thoroughly inspect the remaining components. Check the brake rotor for signs of wear, such as deep grooves, scoring, or excessive rust. If the rotor is worn beyond the manufacturer's specifications (check the minimum thickness stamped on the rotor), it should be replaced. Inspect the brake lines for any cracks, leaks, or damage. Check the brake hoses for swelling or deterioration. Clean all components with brake cleaner to remove dirt, grease, and brake dust. Use a wire brush to clean the caliper bracket and any other metal surfaces. Lubricate the sliding surfaces of the caliper bracket with brake grease to ensure smooth movement of the brake pads.

Installation of New Brakes:

1. Install New Rotor (if applicable): Slide the new rotor onto the hub. Make sure it sits flush against the hub surface. Secure it with a lug nut or a rotor holding screw (if equipped) to prevent it from moving while you work.
2. Install Caliper Bracket (if removed): Reinstall the caliper bracket, tightening the bolts to the manufacturer's specified torque.
3. Install New Brake Pads: Install the new brake pads into the caliper bracket. Make sure they are properly seated and oriented correctly. Refer to the photos you took during disassembly.
4. Retract Caliper Piston: This is a crucial step. You need to retract the caliper piston to make room for the new, thicker brake pads. For most rear brakes, you'll need a special brake caliper tool that both pushes and rotates the piston simultaneously. Follow the tool's instructions carefully. Some calipers require rotating the piston clockwise, while others require counter-clockwise rotation. If you don't have the correct tool, you risk damaging the caliper.
5. Reinstall Caliper: Carefully slide the caliper over the new brake pads and rotor.
6. Install Caliper Bolts: Reinstall the caliper bolts and tighten them to the manufacturer's specified torque.
7. Reinstall Wheel: Reinstall the wheel and tighten the lug nuts by hand.
8. Lower Vehicle: Lower the vehicle to the ground and torque the lug nuts to the manufacturer's specified torque using a torque wrench.
9. Repeat: Repeat the process for the other rear wheel.

Brake Bleeding (if needed):

Brake bleeding is necessary if you opened the brake lines or replaced the brake calipers. This process removes air bubbles from the brake lines, which can compromise braking performance. You'll need a helper for this task.

1. Locate Bleed Screws: Locate the bleed screws on the brake calipers. They are typically small screws with a rubber cap.
2. Attach Bleeding Hose: Attach a clear hose to the bleed screw and submerge the other end of the hose in a container of brake fluid. This prevents air from being drawn back into the system.
3. Open Bleed Screw: Have your helper slowly depress the brake pedal while you open the bleed screw.
4. Close Bleed Screw: Close the bleed screw before your helper releases the brake pedal.
5. Repeat: Repeat steps 3 and 4 until no more air bubbles come out of the hose.
6. Check Fluid Level: Regularly check the brake fluid level in the master cylinder reservoir and add fluid as needed. Never let the reservoir run dry, as this will introduce more air into the system.
7. Repeat for Other Calipers: Repeat the bleeding process for all the brake calipers, following the correct bleeding sequence for your vehicle (typically, the furthest caliper from the master cylinder is bled first).
8. Final Check: After bleeding all the calipers, ensure the brake pedal feels firm and responsive.

Testing & Break-in:

After installing the new brakes, it's crucial to test them and break them in properly. Before starting the engine, pump the brake pedal several times to ensure the brake pads are seated against the rotors. Start the engine and perform a low-speed test stop in a safe area to ensure the brakes are functioning correctly. Avoid hard braking for the first few hundred miles to allow the brake pads to properly seat against the rotors. This "break-in" period allows the brake pads to conform to the rotor surface, maximizing contact area and improving braking performance. During this period, you may notice some noise or vibration, which should gradually diminish as the brakes break in.

Troubleshooting:

Several problems can arise during brake replacement. Stripped bolts can be a frustrating issue. Use penetrating oil and a bolt extractor if necessary. A stuck caliper can be difficult to remove; use a pry bar and gentle pressure. Difficulty retracting the piston often indicates a seized caliper or the need for a specific caliper tool. Noisy brakes after installation can be caused by improper installation, low-quality brake pads, or the need for lubrication. If you encounter problems you cannot resolve, consult online resources or a qualified mechanic.

Parking Brake Adjustment:

The parking brake cable may need adjustment after replacing the rear brakes, especially if the parking brake was not functioning correctly before. Consult your vehicle's repair manual for specific instructions on adjusting the parking brake. The adjustment is typically done by tightening or loosening a cable adjuster located near the parking brake lever or under the vehicle. An improperly adjusted parking brake can lead to premature wear or failure of the parking brake shoes or pads.

Component Compatibility:

Choosing the correct brake components is essential for optimal performance and safety. Consult your vehicle's owner's manual or a parts catalog to ensure the brake pads, rotors, and hardware are compatible with your specific vehicle model and year. Consider the type of driving you do when selecting brake pads. Performance brake pads offer improved stopping power but may produce more noise and dust. Economy brake pads are quieter and cleaner but may not provide the same level of performance.

Frequently Asked Questions

How often should I replace my back brakes?

Brake pad life varies depending on driving habits, vehicle type, and brake pad quality. Typically, back brakes last between 30,000 and 70,000 miles.

What are the signs that my back brakes need replacing?

Common signs include squealing or grinding noises when braking, a soft or spongy brake pedal, longer stopping distances, and a brake warning light on the dashboard.

Can I replace just the brake pads and not the rotors?

Yes, if the rotors are still within the manufacturer's specifications and are not excessively worn or damaged. However, it's often recommended to replace both pads and rotors at the same time for optimal performance.

How much does it cost to replace back brakes?

The cost varies depending on the vehicle, the quality of the parts, and whether you do it yourself or hire a mechanic. DIY replacement typically costs between $50 and $200, while professional installation can range from $200 to $500 or more.

Do I need to bleed the brakes after replacing the pads?

If you did not open the brake lines during the pad replacement, bleeding is generally not required. However, if you replaced the calipers or opened the brake lines, bleeding is essential to remove air bubbles.

Conclusion

Replacing your back brakes is a manageable DIY project that can save you money and increase your confidence in vehicle maintenance. By following these steps, taking necessary safety precautions, and ensuring proper component compatibility, you can successfully complete the job and enjoy safe and reliable braking performance. Remember to always prioritize safety and consult a professional mechanic if you encounter any difficulties or uncertainties.