Wilwood Rear GT-Rotor and Red AERO4 Caliper Package for BMW 323i/328i/325i, Retains the Specified Original Parking Brake

Red AERO4 calipers operate the GT-slotted rear rotors in this package for the specified BMW applications. Iron hats retain the correct original parking-brake drum interface, keeping mechanical parking operation separate from the four-piston service calipers. Bill Wood established Wilwood Engineering in 1977; the company is based in Camarillo, California. Its disc brake design and manufacturing range covers calipers, rotors, master cylinders, valves, fittings and brake lines, as well as complete systems. Those products serve motorsport, street-performance and specialized applications, with the individual components selected to match the braking system as a whole.

Technical Details

• Calipers: 4 stainless pistons per caliper; radial mounting; forged aluminium bodies. Color: Red. Finish: Red Powder Coat. Inlet thread: 1/8-27 NPT.
• Caliper family: AERO4. Brake-pad compound: BP-20.

• 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-R. 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.

Fitment & Compatibility

Match each model's year, body style and drivetrain in the table below. Verify that the retained parking shoes and hub correspond to the hat dimensions, then check the complete 18-inch wheel envelope and routing of the supplied eight-inch rear flexlines.

Manufacturer Documents

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

PMB Performance brings over 20 years of parts and brake-fitment experience to helping you select the correct configuration. Send the vehicle details and measured brake interfaces if you need help confirming this kit.