Wilwood Black Four-Piston Rear Brake Conversion for BMW 325i/328i/323i, Drilled 14-Inch Rotors and OE Parking-Brake Hats

Drilled-and-slotted rotor rings and black four-piston AERO4 calipers identify this BMW rear configuration. The iron hats preserve the specified factory parking-brake interface, while BP-10 pads and the supplied flexlines complete the service-brake components. Wilwood Engineering is based in Camarillo, California. Bill Wood founded its disc brake system and component business in 1977. The manufacturer designs and produces calipers, brake rotors, master cylinders, valves, fittings and brake lines for motorsport, street-performance and specialized uses. Each item must suit the rest of the brake system.

Technical Details

• Manufacturer: Wilwood; manufacturer part number: 140-13583-D. Supplied quantity: Sold as a kit.
• Application category: Rear Brake Kits - Street Performance. Axle/spindle category: Rear Kits. Brake function: Disc; Parking.
• Separate wheel hubs included: No. Retain only the hub arrangement specified for this kit.
• Mounting hardware included: Yes. Spindles included: No. Master cylinder included: No. Brake booster included: No.
• Flexible brake lines included: Yes; matched line kit 220-13647, 8.00 inches nominal length.
• The rotor hats retain the specified original mechanical parking-brake shoes and assembly; a replacement parking-brake mechanism is not supplied.

• Rotor: 14.00 in; 355.6 mm outside diameter; 1.10 in; 27.94 mm thickness. Material: Spec-37 Iron. Construction: Vented. Friction-face style: SRP Drilled & Slotted.
• Rotor-hat material: Iron. Hat offset: 1.700 inches; this hat dimension is separate from axle offset.
• Rotor surface finish: Black Electro Coat.

• Wheel interface: 5 x 4.72 in; 5 x 119.89 mm. Rotor/hat wheel-stud clearance: 0.490 in; 12.45 mm.
• Nominal minimum wheel diameter: 18 in; 457.2 mm. Verify the full wheel-clearance drawing; diameter alone does not establish barrel or spoke clearance.
• Housing/spindle flange: OEM. Flange/axle offset: 0.00 in; 0 mm.

• Calipers: 4 stainless pistons per caliper; radial mounting; forged aluminium bodies. Color: Black. Finish: Black Powder Coat. Inlet thread: 1/8-27 NPT.
• Caliper family: AERO4. Brake-pad compound: BP-10.

Fitment & Compatibility

Verify the exact 323i/325i/328i model, body and year below, including Canadian sedan and RWD-only conditions. The existing parking assembly and hub must match the hat. Use the wheel diagram to confirm barrel and spoke space around the 14-inch rotor package.

Use the fitment table below for the complete model, year, submodel and brake-option conditions; every listed condition must match the installed vehicle.

Manufacturer Documents

• Wilwood product specifications and wheel-clearance drawing
• Installation instructions

Supply the vehicle details and current brake configuration when contacting PMB Performance for fitment help. Our team brings over 20 years of parts experience to checking the combination.