Replacing rear brakes on vehicles with electronic parking brakes (EPB) can seem daunting. Many believe a specialized scan tool is necessary to retract the caliper pistons. However, with the right tools and technique, it’s possible to service electric rear brakes without a scan tool. This guide provides a step-by-step approach to replacing rear brake pads and rotors on vehicles equipped with EPB systems.
Replacing front brakes remains a straightforward process, similar to traditional brake jobs. However, rear brakes with EPB require a specific tool to rotate the pistons inward, effectively disengaging the internal parking brake mechanism. This tool, often referred to as a “piston rewind tool,” is readily available and relatively inexpensive. Crucially, use a right-hand threaded tool, allowing you to turn both driver and passenger side pistons clockwise.
Before beginning, locate the electrical connector for the EPB motor, usually found behind the rotor shield at the bottom of the wheel hub (6 o’clock position). Carefully detach the wire from its securing clip to provide slack for caliper movement. Unplugging the motor entirely is unnecessary. Although space is limited with the brake line and electrical connector, maneuvering the caliper is still possible.
Next, remove the pad retaining spring clip, exercising caution due to its potential stored energy. Applying pressure to the top of the spring while using a slotted screwdriver to release the bottom clip is recommended. Remove both caliper guide pins after taking off their protective caps (typically requiring a 7mm Allen key). Rotate the caliper body towards the rear of the vehicle and secure it to the strut spring using an S-hook. This provides ample working space for subsequent steps. Proceed to remove the old brake pads.
Before compressing the piston, open the brake fluid reservoir cap to prevent pressure buildup and potential overflow. Monitor the fluid level throughout the compression process. Cover the open reservoir with a clean rag to prevent contamination.
The threads on the piston rewind tool and the internal EPB mechanism might not perfectly match, resulting in the piston retracting faster than the tool expands. To address this, turn the tool a few times and then tighten the jam nut. This action pushes the piston inward until resistance is felt. Repeat this process until the piston is fully retracted.
While some suggest avoiding grease on the piston face due to potential interference with braking performance, this remains debatable. If no grease was present initially, applying a fresh layer to other metal-to-metal contact points—excluding the piston face—is advisable. Always grease the caliper guide pins to prevent sticking and ensure smooth operation.
Reassemble the components, ensuring proper torque on the guide pins (refer to your vehicle’s specifications as front and rear torque values often differ). Reinstall the retaining spring, secure the EPB wire, and remove the S-hook. Close the brake fluid reservoir cap.
After completing the installation, gently depress the brake pedal several times with the engine off. Start the engine and repeat the process until firm brake pressure is established. Cycle the parking brake numerous times (approximately 10) to ensure proper engagement and release. Finally, take a short drive to allow the new pads to bed in. After the brakes have cooled, cycle the parking brake a few more times.
This method allows for a successful brake job without dealership visits, expensive scan tools, or specialized maintenance modes. By understanding the mechanics of the EPB system and employing the correct technique, replacing electric rear brakes can be accomplished efficiently and effectively.
