Wilwood Rear AERO4 Kit for BMW 323i/325i/328i, Black Calipers and 14-Inch GT Rotors for the Original Parking Brake, Selected 2006–2013

This BMW rear kit combines black AERO4 calipers with 14-inch GT-slotted rotors and iron parking-brake hats. The hats work with the matched original parking-shoe assembly; the package does not provide a complete replacement parking-brake mechanism or a new rear hub. Founded by Bill Wood in 1977, Camarillo, California-based Wilwood Engineering designs and manufactures disc brake systems and their components. Calipers, brake rotors, master cylinders, valves, fittings and brake lines form its range for motorsport, street-performance and specialized applications. Compatibility depends on choosing those parts around the complete braking system.

Technical Details

• 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.

• Manufacturer: Wilwood; manufacturer part number: 140-13583. 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: GT Slotted.
• Rotor-hat material: Iron. Hat offset: 1.700 inches; this hat dimension is separate from axle offset.
• Rotor surface finish: Black Electro Coat.

• 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-20.

Fitment & Compatibility

Select only the 323i, 325i and 328i body/year combinations below; the broader front-kit model list must not be carried over to this rear kit. Check the factory parking brake, RWD restrictions and the 18-inch wheel envelope in DS1039. Rear flexlines are included.

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

Ask PMB Performance for assistance if the installed hardware differs from the documented application. With over 20 years of parts and fitment experience, we can help identify the measurements needed to check the conversion.