Mazda CX-5 Rear Brake & EPB Service Guide

Maintaining your vehicle's braking system is paramount for safety and performance. For owners of the second-generation Mazda CX-5, specifically models from 2017 to 2022, equipped with the Electric Parking Brake (EPB), changing the rear brake pads involves a few specific steps that differ significantly from traditional braking systems. This detailed guide, crafted by an experienced auto mechanic, will walk you through the entire process of replacing your rear disc brake pads, lubricating caliper slide pins, and even replacing the rotors if necessary. By following these instructions carefully, you can confidently undertake this DIY task, ensuring your CX-5 continues to provide reliable stopping power for years to come.

Understanding Your Mazda CX-5's EPB System

The Electric Parking Brake (EPB) system in your Mazda CX-5 replaces the conventional handbrake lever with an electronic switch. While convenient, it requires a special procedure to retract the caliper pistons during brake pad replacement. Failing to place the EPB system into maintenance mode can lead to severe damage to the EPB actuator motors, which are integrated into the rear calipers. These motors need to be fully retracted to allow sufficient space for the thicker new brake pads and to prevent internal damage when the pistons are compressed. Always proceed with caution and at your own risk when performing this maintenance.

Essential Tools and Compatible Parts

Before you begin, gather all the necessary tools and replacement parts. Having everything ready will streamline the process and prevent interruptions:

• Lug nut wrench / Tyre iron
• Floor jack
• Two jack stands
• Wheel chocks
• 14mm socket with a 3/8" drive ratchet
• "F" clamp or disc brake expander tool
• Tube of brake caliper grease (synthetic recommended)
• Brake parts cleaner spray
• 10mm wrench (for brake bleeding, if necessary)

Compatible Rear Brake Pads:

• Power Stop 16-1846
• ACDelco 17D1846CH
• Raybestos EHT1846H
• KFE KFE1846-104

Compatible Rear Brake Rotors (If Replacement is Needed):

• DuraGo BR90119602
• Raybestos 981008R
• ACDelco 18A2964AC

Prioritising Safety: Initial Vehicle Preparation

Safety is paramount when working on your vehicle. Ensure your Mazda CX-5 is on a level, stable surface. Shift the transmission into "P" (Park) and turn off the ignition. To prevent any unexpected movement, place wheel chocks on both sides of the front tyres.

Before proceeding with pad replacement, the Electric Parking Brake must be released. Push down on the brake pedal, and then push down on the EPB switch, which is typically located at the rear left (driver) side corner of the gear selector assembly. You should hear the two rear EPB actuator motors make a distinct noise for about a second or two as they release. The red "(!) BRAKE" symbol on your speedometer should also turn off.

Engaging Electric Parking Brake (EPB) Service Mode

This is the most critical step for EPB-equipped CX-5 models. The EPB system must be placed into "service" or "maintenance" mode to fully retract the parking brake actuator motors. This allows the rear caliper pistons to be easily compressed, making room for the thicker new brake pads without damaging the EPB motors. There are a couple of methods to achieve this:

Method 1: DIY Mazda Procedure (For 2017-2022 CX-5)

Mazda has provided a user-friendly method for owners to engage EPB service mode without special diagnostic tools. Ensure your front wheels are blocked and the transmission is in "Park".

1. Switch the ignition to "ON" but do NOT start the engine. You will need to press the "START" button twice: once for "accessory power" and then again to turn the ignition system on. Keep your foot off the brake pedal.
2. If you haven't already, release the parking brake by placing your foot on the brake pedal and then pushing down on the EPB switch near the gear selector.
3. Release the brake pedal.
4. Press the accelerator (gas) pedal all the way down and, at the same time, push down the EPB switch. Hold both in this position.
5. With your free hand, press the "START" button three times rapidly in a row while continuing to hold down the accelerator and EPB switch.
6. Turn the ignition to "OFF".

If you completed the procedure correctly, you will hear the EPB actuator motors making a whirring noise for a few seconds as they wind all the way back. You should also see the yellow "(P!)" symbol illuminate on your tachometer (RPM gauge), indicating that maintenance mode is active.

Method 2: Alternative from CX-5 Service Manual (For 2016-2019 CX-5)

The official Mazda CX-5 shop manual for certain years provides a slightly different set of instructions. This is useful if Method 1 does not work for your specific vehicle. Again, ensure wheel chocks are in place and the transmission is in "Park".

1. Switch the ignition ON (engine off).
2. Release the electric parking brake.
3. Switch the ignition to OFF, and then switch the ignition to ON within 5 seconds while simultaneously pressing down the EPB switch and fully depressing the accelerator pedal.
4. Verify that the "(P!)" warning light is illuminated in an amber colour, confirming that the system has switched to maintenance mode.
5. Switch the ignition to OFF.

Lifting the Vehicle and Removing the Wheel

With the EPB in service mode, you can now proceed with physically accessing the brakes. Slightly loosen the five lug nuts on the rear wheel by turning them about half a turn in the counterclockwise direction using your tyre iron.

Carefully raise the rear of your SUV with the floor jack. Once lifted, securely support the vehicle with at least two jack stands. Never solely rely on the floor jack to support the vehicle. Spin off the five lug nuts completely in the counterclockwise direction and set them aside in a safe place.

Carefully remove the rear wheel and tyre. For added safety, some home mechanics choose to place the removed wheel and tyre under the vehicle's frame rail as an extra support, just in case the vehicle inadvertently falls off the jack stands.

Accessing the Rear Brake Caliper

With the wheel off, you will clearly see the rear caliper, brake bracket, rotor, the EPB actuator motor housing, and surrounding suspension components. The rear brake caliper is secured to the bracket by two bolts located on its backside, with the bolt heads facing towards the cargo area of the SUV. Some owners find it beneficial to disconnect the power plug for the EPB motor at this stage to make caliper removal easier.

Using your 14mm socket and a 3/8" drive ratchet, loosen the top caliper bolt. When viewed from the outside of the vehicle, you will turn it in the clockwise direction. Similarly, loosen the bottom caliper bolt by turning it clockwise from the outside. Note: If you were positioned underneath the vehicle, looking at the back of the rotor and caliper, you would loosen these bolts in the "normal" counterclockwise direction. Since we are working from the outside, our orientation is reversed. Once loosened, spin out the two bolts by hand and place them somewhere safe.

Caliper Removal and Pad Inspection

Carefully lift the caliper off the old pads and out of the bracket. Avoid stressing, pulling, kinking, or bending the rubber brake fluid hose; you can rest the caliper on the rotor or suspend it from the suspension spring with a bungee cord or twine.

Your rear caliper piston should be aligned with specific "grooves" (notches or cut-out sections) to fit securely over a peg at the middle of the inner brake pad. Make a mental note of this orientation for reassembly.

Remove the old inner and outer brake pads from the bracket. Pay attention to the position of the wear indicator bars or "squeal" bars on the old pads. On the 2019 CX-5, these wear indicator bars were typically situated at the bottom of both the inner and outer brake pads.

Preparing for New Pads: Cleaning and Lubrication

If your new set of rear pads includes replacement brake hardware, pull the old pad abutment clips (also known as "anti-rattle" clips) from the top and bottom of the bracket. Thoroughly clean the rotor, lug studs, caliper, and bracket using brake parts cleaner spray. When cleaning, avoid breathing in the brake dust or the cleaning spray, as they may contain carcinogenic substances.

Apply a thin layer of synthetic brake parts lubricant grease to the new pad abutment clips where they will contact the bracket or the new pads. Push the new pad abutment clips firmly into the top and bottom of the bracket.

For the caliper to operate smoothly, the two slide pins (also called "slider" pins or "guide" pins) require proper lubrication. It is important not to mix up the top and bottom caliper slide pins, as they are slightly different. Pull out one slide pin at a time, apply a thin layer of caliper grease to the pin, and then push it back into its rubber dust boot attached to the bracket. Repeat this process for the other caliper slide pin.

Compressing the Caliper Piston

This step is crucial and directly tied to the EPB system. If your SUV is equipped with the EPB, it MUST be in maintenance mode before attempting to compress the piston. If correctly engaged, the actuator motors will be fully retracted, allowing the piston to be easily compressed into the caliper. You should have heard the motors whirring and a metallic clunk indicating the actuator rods are fully retracted. Attempting to compress the piston without the EPB in service mode can cause severe damage to the actuator motors. Proceed with extreme caution and at your own risk!

Attach an "F" clamp to the caliper, using the back of an old brake pad to evenly distribute pressure across the piston. It is important to avoid turning or rotating the piston while compressing it. Slowly turn the "F" clamp handle in the clockwise direction to push the piston back. If you encounter any significant resistance, stop immediately and re-verify that the EPB system is indeed in maintenance mode.

To facilitate piston compression, remove the brake fluid reservoir cap in the engine bay. This allows the fluid to flow back more easily. Be sure to replace the reservoir cap as soon as you are done compressing the piston. Continue compressing the piston until it is almost flush with the rubber dust boot surrounding it.

The Mazda service manual contains a specific warning: "CAUTION - If the piston is pushed into caliper while rotating the piston, the caliper internal parts could be DAMAGED. Be careful NOT to rotate the piston when pushing the piston into the caliper." The manual often depicts the use of a "disc brake expander tool" to push the piston straight back, which is the preferred method to avoid rotation.

Rotor Assessment and Replacement (If Required)

If your CX-5 has been exhibiting shuddering, vibrations, or shaking in the rear end specifically when braking, your original rear brake rotors might be worn out or warped from excessive heat, and should be replaced. If your rotors appear smooth and free of deep grooves or uneven wear, you might be able to reuse them with new pads. However, for optimal braking performance and longevity, replacing rotors along with pads is often recommended.

Steps for Rotor Replacement:

1. Remove the two 14mm bolts located on the backside of the caliper bracket that attach it to the steering knuckle.
2. Pull off the entire bracket assembly and set it aside in a safe place with its bolts.
3. Some Mazda models may have a small set screw on the outer face of the rotor that needs to be removed before it can be pulled off.
4. Slide the old rotor straight off the lug studs. If it's stuck due to rust or debris, firmly hit it a few times with a rubber mallet to loosen it. Do not use a metal hammer directly on the rotor.
5. Clean off the lug studs and the wheel hub surface thoroughly with brake parts cleaner spray.
6. Slide the new rotor over the lug studs. If equipped, replace the set screw.
7. Lower the bracket back into place and spin in the two 14mm bolts by hand to prevent cross-threading. Tighten these bolts until they are snug. According to the 2016-2019 Mazda CX-5 service manual, these 14mm rear caliper bracket bolts should be tightened to 63 to 75 lb-ft (or 85 to 102 N-m) of torque. A torque wrench is essential for this step.

Installing New Brake Pads and Reassembling the Caliper

Install the new outer and inner brake pads into the bracket. Ensure the wear indicator bars are situated at the bottom of both pads, mirroring the original setup. Push the two pads together until they are flush against the rotor.

You may have noticed that both the old OEM pads and your new pads are equipped with small pegs near the middle of each pad. The rear caliper piston needs to be in the correct orientation for its "grooves" to fit securely over the peg on the inner brake pad. If, for some reason, the piston is not correctly lined up, you can slowly and carefully rotate the piston in the clockwise direction using a disc brake piston tool, such as the Lisle 28600, or even a pair of needle-nose pliers can work in a pinch. Double-check that the caliper piston is in the correct position before proceeding.

Carefully lower the caliper over the new brake pads and into the bracket. Line up the bolt holes in the caliper with their corresponding holes in the slide pins within the bracket. Spin in the two caliper bolts a few turns by hand in the counterclockwise direction (as seen from the outside of the SUV) to help prevent them from becoming cross-threaded. Tighten the caliper bolts by turning them in the counterclockwise direction with your 14mm socket and 3/8" drive ratchet until they are snug.

If you have a sensitive and reliable torque wrench, the 2016-2019 CX-5 service manual lists a torque specification of 17 to 22 lb-ft (or 22 to 31 N-m) for these 14mm caliper bolts. Double-check that both the bracket bolts and the caliper bolts are tight before moving on.

Brake Fluid Bleeding (Recommended)

If your brake pedal has been feeling soft or spongy, or if there's any concern about air bubbles or moisture in your brake fluid, it is highly recommended to bleed the brake lines and flush out the old fluid with fresh DOT 3 brake fluid at this time. Using a bleeder bottle, such as the Allstar Performance Bleeder Bottle, can make this a simple one-person job, as it features a one-way check valve to prevent air re-entry.

The brake fluid bleeder valve is located on the backside of the caliper, just below the top bolt. You'll need a 10mm wrench to open and close these valves. Generally, the brake line bleeding order for most vehicles starts at the caliper furthest from the brake fluid reservoir and then works its way to the closest caliper. For the CX-5, this order is most likely: right rear, left rear, front right, and front left.

The torque specification for tightening the rear caliper bleeder valves is typically 61 to 86 in.lbf (or 6.9 to 9.8 N-m). Avoid over-tightening these valves to prevent stripping the threads or causing damage that could lead to a brake fluid leak. While a torque wrench is ideal, many mechanics tighten these until they are snug, avoiding excessive force.

Final Reassembly and Post-Maintenance Checks

Carefully push the rear wheel back into place over the lug studs. Spin on the five lug nuts a few turns by hand in the clockwise direction to help prevent cross-threading. Slightly tighten the lug nuts in a "criss-cross" or star pattern with the lug nut wrench. Once the vehicle is back on the ground, fully tighten the lug nuts to the manufacturer's specified torque, again using a star pattern, to ensure even pressure and proper wheel seating.

Exiting EPB Service Mode

It is crucial to exit EPB service mode once the brake work is complete. While specific instructions for exiting service mode were mentioned to be provided at the end of the original guide, they are not present in the provided information. Therefore, it is imperative to consult your Mazda CX-5's owner's manual or a reliable workshop manual for the precise steps to safely disengage the EPB maintenance mode. Typically, this involves a specific sequence of ignition cycles and EPB switch presses, often reversing the entry procedure, to ensure the system is fully re-engaged and operational before driving. Once out of maintenance mode, pump the brake pedal several times to seat the new pads against the rotors and restore firm pedal pressure.

Frequently Asked Questions (FAQs)

Q: How often should I replace my Mazda CX-5's rear brake pads?

A: Brake pad lifespan varies greatly depending on driving habits, terrain, and the type of pads. Generally, rear brake pads on a CX-5 might last anywhere from 30,000 to 70,000 miles. It's best practice to inspect them during every tyre rotation or oil change, or at least annually.

Q: What are the signs that my brake pads need replacing?

A: Common signs include a squealing or grinding noise when braking, a vibrating or pulsating brake pedal (often due to warped rotors), the vehicle pulling to one side when braking, or a noticeable decrease in braking performance. Many pads also have wear indicators that produce a high-pitched squeal when they are low.

Q: Can I replace just the pads, or do I always need new rotors?

A: If your rotors are smooth, free of deep grooves, and show no signs of warping (like shuddering during braking), you might be able to replace just the pads. However, for optimal performance and longevity, especially if you've experienced issues like vibrations, replacing the rotors along with the pads is often recommended. This ensures a fresh, flat surface for the new pads to bed into.

Q: What if my EPB doesn't go into maintenance mode?

A: If you've followed the instructions carefully and the EPB system doesn't enter maintenance mode (no yellow (P!) light, no whirring sound), re-attempt the procedure precisely. If it still fails, there might be an issue with the EPB system itself, or your specific vehicle year/trim might require a diagnostic scan tool (OBD2 scanner) to engage the mode. In such cases, it's advisable to consult a professional mechanic.

Q: Why is it important to lubricate the slide pins?

A: Caliper slide pins allow the brake caliper to move freely back and forth as the pads wear and as the brake pedal is applied and released. If these pins seize due to lack of lubrication or corrosion, the caliper can get stuck, leading to uneven pad wear, reduced braking efficiency, and potentially overheating of the brakes. Proper lubrication ensures smooth and even braking performance.

By following this comprehensive guide, you've gained the knowledge and confidence to tackle your Mazda CX-5's rear brake maintenance. Remember, proper brake function is crucial for your safety and the longevity of your vehicle. If you ever feel unsure or encounter unexpected issues, do not hesitate to consult a qualified automotive technician.

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