These brake rotors can only be fitted a certain way on the M3 models as they are directional and on the ones used M3 the left side rotor will have a part number ending in odd while right side rotor part number will have digits ending in even numbers. First immobilize the rear wheels and engage the parking brake, then turn the nuts of the front wheels anti-clockwise by a quarter and jack up to take out the wheels. Do not disconnect or unbolt the
Brake Caliper fluid hose; this should be retained mechanically with mechanic's wire to the caliper assembly. Go further to loosen the brake caliper and the caliper bracket, to eliminative the special shouldered recessed hex fastener if possible by utilising a 6mm hex socket, although penetrating lube should be applied if required. If, for example, the brake rotor is seized do not Vice, you can try: Loosen the retaining bolt, spray some lubrication on the rotor to hub joint, set two wheel bolts on the shaft and hit with a hammer until the rotor will leave the hub without damaging the machined area. For installation, inspect the rotor and then, to ensure better adhesion between the hub and brake rotor, clean the hub and brake rotor surfaces and applied a light coat of anti seizing compound and tightened the retaining fastener to 12 ft lbs. The rest of the procedures are the reversal of the removal process, hand tightening the lug bolts, raising the car, and final tightening of the lug bolts in a diagonal manner on 66-81 ft. lb. After controlling the brake pedal to get a firm feeling, 'bed-in' the rotors by coming to a complete stop from 30 mph, let them cool before repeating the process. Some signs include: slight irregularities, pits, cracks on the brake rotor; warpage and varying thickness through feeler gauge to assess for pulsation during braking . Check for defects where calipers or pads have been unbolted as this will give way to cracks or warping which is dangerous. Slight catches are permitted however massive scoring or warping warrants refinishing or replacing of the piece. New rotors should be refinished; make sure that the final coating is removed before the rotors are used; check hub run-out, 0.002 inch is the maximum allowed. To do proper rotor assessment, lift the vehicle; then, take off the tyre; put the lug bolts back but remove
Brake Pads. Check the minimum thickness with a dial indicator and measure the run out; if it is more than 0.004, do it again. Using a micrometer the rotor thickness and parallelism should be measured to reach specified values, if during machining the value was obtained below the minimum then the rotor should be replaced.