BMW 34112226813 Ventilated Brake Disc

M3 brake rotors work best when positioned a specific way. The left takes an odd-numbered part number, while the right uses an even-numbered end. Start by locking the rear wheels and using the parking brake. Loosen front wheel bolts just a little, then lift the car up and remove the front wheels. Keep the brake caliper fluid hose connected during wheel removal, and hold the caliper assembly with mechanic's wire to give it support. Pull the brake caliper and bracket out, use your 6mm socket tool to take off the tight special shouldered recessed hex fastener, and apply penetrating lubricant if needed. You can free a stuck brake rotor by first loosening the hold-down bolt then spraying lubricant around the rotor's edge, using two wheel studs to gently tap the rotor off without damaging the flat part of the hub. When putting the parts back on, check and clean the rotor first. Apply anti-seizing compound to protect it, and tighten the retention bolt to 12 foot-pounds. Do the reverse to put it all together. Make sure you tighten the lug nuts in a crossing pattern, applying 66-81 foot-pounds of force to each pair. Simultaneously press down slowly on the brake pedal to set brake strength, then released it with repeated stops to get rid of buildup on the rotors. Check the rotor for surface defects, like pits and cracks, look for unevenness, and size up excessive ridges. Measure surface flatness and overall thickness, and replace if you spot any problems. A little surface wear is OK, but severe markings and bowing needs fresh finish or replacement. Before fitting new rotors, remove any protective covering from them. Then check that your hub runs straight, keeping in mind that too much run-out should be under 0.002 inch. To check your rotors right, lift the vehicle, take off the tire, fit the lug nuts back in place, then take out the brake pads. When measuring runout, use a dial indicator. You should replace rotors when the number exceeds 0.004 inches. Then check for thinness and flatness.

The brake discs in M3 cars act in opposite directions and have different part numbers for left and right wheels: the left one ends with an odd number; the right one with an even number. Before working, block the front tires while you turn rear wheel bolts by 1.4 turns. Take off your rear wheels by lifting the rear of the car, and don't disconnect the fluid hose; keep the caliper assembly steady with mechanic's wire to prevent damage to the line. Take out both the brake caliper and its mounting bracket. Turn the 6mm hex socket tool (and some compression spray) until you free the unique fastener with its built-in notch. To free a stuck brake rotor, first loosen the retaining bolt just 3 turns. Spray oil around the rotor contact point with the hub, then thread in two wheel bolts about 10 turns each. Tap the stationary rotor firmly from its flat side to break it loose. When installing the rotor, make sure it's good condition, remove any protective coating, and continue installing. Wash both rotor and hub surfaces clean, spray on anti-seize grease, and install the rotor onto the hub using a 12 ft. pound (16 Newton-meter) torque. Tighten the parking brake until it holds, then put on the wheels and secure them with hand tightening on the lug bolts. Move the vehicle until tires touch the ground, and apply enough turning pressure to lug bolts using a cross-pattern for 66-81 ft. lbs. (90-110 Nm). To make sure your brakes stop you whenever you need them, do this: bring the car to a complete stop five times at 30 mph, wait for your brakes to cool, do it all over again for another 5 stops, then repeat if needed. You perform the same inspection steps to check the rear brake rotor as you do the front one.