BMW 318/325/M3/525/535/M5 1989-1993 Repair Information

Brake Rotor

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REMOVAL & INSTALLATION



The balancing clips in the venting of the rotor must not be moved or removed. This will cause an imbalance of the rotor.

  1. Raise and support the vehicle. Remove the front wheels.
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  3. Remove the caliper without disconnecting the brake line. Hang the caliper with a piece of wire so no tension is put on the brake line.
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  5. Remove the internal hex bolt from the hub and pull the rotor off the hub.
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  7. Check the rotor and replace as necessary. Install the rotor and caliper. Install the wheels.
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  9. Burnish the rotors by making 5 full stops from 30 mph (50 km/h), then allow the brakes to cool. Make 5 additional stops from 30 mph (50 km/h) and allow the brakes to cool again. This will burnish the rotors and allow full braking efficiency.
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INSPECTION



  1. Use a micrometer to measure the thickness of the rotor at 8 points around the circumference. The rotor measurements should not deviate more than 0.0008 inches (0.02mm) from largest to smallest.
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  3. The minimum machining thickness is 0.803 inches (20.4mm) except for the M3 which has a machining thickness of 0.921 inches (23.4mm) and the M5 whose rotors must not be machined. The minimum wear thickness is 0.787 inches (20.0mm) except for the M3 which is 0.906 inches (23.0mm) and the M5 which is 1.039 inches (26.4mm).
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  5. Remove the caliper or retract the brake pads. Bolt the rotor to the hub. Install a dial indicator with the tip perpendicular to the friction surface of the rotor. With the wheel bearings in serviceable condition, the axial runout must not exceed 0.008 inches (0.2mm).
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  7. Replace or machine the rotors on both sides if found defective.
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