The Complete Guide: DIY Rear Brake Pad Replacement on G80 M3 & G82 M4

BMW G8X G80 G82 M3 M4 Carbon Fiber GT Style Grill

Completing the brake service on your G8X M3/M4 means replacing the rear pads. This process is just as important for maintaining brake balance, safety, and performance. Using iSWEEP Rear Brake Pads ensures you have a perfect performance match to the front set, delivering stable, confident stops with the added benefit of low dust.

This guide will walk you through the entire rear brake pad replacement, with a special focus on the most critical step: safely retracting the electronic parking brake.

Table of Contents

  • Crucial First Step: The Electronic Parking Brake (EPB)

  • Tools & Parts Needed for the Job

  • Step-by-Step Rear Brake Pad Installation

  • The Bedding-In Process

  • Frequently Asked Questions (FAQ)

Crucial First Step: The Electronic Parking Brake (EPB) - READ THIS FIRST!

Unlike the front brakes, your rear calipers have an electronic motor for the parking brake. You cannot simply push the piston back with a tool. Attempting to do so will permanently damage the expensive caliper actuator.

To perform this job, you must use a diagnostic tool to put the rear brakes into "Service Mode." This electronically retracts the piston for you. The most common methods are:

  1. A high-quality OBD2 Scan Tool: Tools from brands like Autel, Foxwell, or Schwaben have a dedicated "Brake Service" or "EPB Retraction" function in their menus. This is the most popular and reliable method for DIYers.

  2. BMW ISTA Software: This is the dealership-level software that can be run on a laptop with the proper cable.

Tools & Parts Needed for the Job

Required Tools:

  • OBD2 Diagnostic Scan Tool with EPB Service Function (Essential!)

  • Floor Jack & Jack Stands

  • 17mm Socket & Breaker Bar

  • Ratchet and Socket Set (typically 16mm or 18mm for caliper bolts)

  • Wire Brush

  • Torque Wrench

Required Parts:

Step-by-Step Rear Brake Pad Installation

  1. Engage EPB Service Mode: Before lifting the car, connect your scan tool to the OBD2 port under the dash. Navigate to the electronic parking brake service menu and follow the on-screen prompts to fully retract the rear caliper pistons. You should hear the motors in the rear calipers whirring. Once complete, leave the tool connected but turn off the ignition.

  2. Lift the Vehicle & Remove Wheels: Chock the front wheels. Loosen the rear lug bolts, then lift the rear of the car and secure it on jack stands. Remove the wheels.

  3. Unplug the Rear Wear Sensor: On the right rear wheel, locate the wear sensor plug. Disconnect it and unclip the wire from its guides.

  4. Remove Caliper & Old Pads: Remove the two main caliper mounting bolts. Slide the caliper off the rotor and, without letting it hang by the brake line, remove the old brake pads. The piston should already be fully retracted from Step 1.

  5. Install New iSWEEP Pads: Clean the caliper carrier with a wire brush. Apply a thin layer of brake grease to the contact points on the back of your new iSWEEP rear pads and slide them into place. Install the new wear sensor onto the inner pad.

  6. Reassemble: Reinstall the caliper over the new pads and torque the mounting bolts to spec. Reconnect the new wear sensor.

  7. Final Torque: Reinstall the wheels and hand-tighten the lug bolts. Lower the car, then use your torque wrench to tighten the lugs to the factory specification (140 Nm / 103 ft-lbs).

  8. Disengage EPB Service Mode: Turn the ignition on, navigate back to the EPB menu on your scan tool, and follow the prompts to re-engage or "exit" service mode. This will calibrate the piston to the new, thicker pads.

The Bedding-In Process

Follow the same bedding-in procedure as the front brakes to ensure a perfect transfer layer is established on the rotors for smooth, quiet, and powerful braking.

Complete Your High-Performance Brake Setup

For a perfectly balanced system with low dust and incredible stopping power, match your new rear pads with our front-axle set and our DIY guide.

Frequently Asked Questions (FAQ)

  • Can I retract the EPB without a scan tool? It is not recommended. Attempting to physically force the piston back will destroy the internal electronic actuator, leading to a very expensive repair. The scan tool is a required part of the job.

  • Is the rear brake pad replacement harder than the front? Mechanically, it's very similar and just as easy. The only difference is the added electronic steps at the beginning and end of the process.

 

Back to BLOG