Wilwood Red Superlite 4R Rear Brake Conversion with 12.88-Inch GT Slotted Rotors and Electronic Parking, 2.50-Inch New-Style Big Ford

For a rear axle that meets the specified new-style Big Ford interface, this kit pairs red four-piston Superlite calipers with GT slotted Spec-37 iron rotors. Their 12.88 × 1.10-inch dimensions differ from the larger 14-inch packages. Separate electric parking calipers remove the need for mechanical parking cables, while an included controller and wiring operate the static holding function. Wilwood Engineering was established in 1977 by Bill Wood in Camarillo, California. The company designs and manufactures disc-brake systems and components, from calipers and rotors to master cylinders, valves, fittings and brake lines, for motorsport, street-performance and specialized installations. Each component must match the rest of the brake system.

Technical Details

• Manufacturer part number: 140-15844-R. Quantity: one kit for the stated axle/application.
• Separate electronic parking calipers, controller, wiring harness and switch are included. EPB actuation is electrical; hydraulic service braking remains independent.
• Mounting hardware and the specified pads are included. Spindles, master cylinder and brake booster are not supplied.
• Service caliper: Forged Narrow Superlite 4R; 4 pistons; stainless piston material. Radial mounting, red powder coat finish.
• Published piston bores: 1.12, 1.12 inches. Supplied pad compound: BP-10.
• Caliper hydraulic inlet: 1/8-27 NPT.
• Rear housing interface: Big Ford New Style; axle offset: 2.50 in; 63.5 mm.
• Rotor specification: 12.88-inch outside diameter × 1.10-inch thickness; GT slotted faces. Spec-37 Iron construction; GT 48 Curved Vane design; published vane configuration: 48 CV.
• Rotor hats: aluminum, black e-coat finish; Big Brake Hat - Flared Bell. Hat offset: 2.035 inch.
• No replacement wheel hubs are supplied; retain or provide the documented matching hub arrangement.
• Wheel mounting patterns: 5 x 4.50; 5 x 4.75; 5 x 5.00 inches.
• Minimum nominal wheel diameter: 17 inches. The wheel must also clear the actual caliper and rotor profile in the installation drawing.
• Brake hoses are not included. Select suitable braided lines and fittings for the installation.

Fitment & Compatibility

Application is controlled by the Big Ford new-style housing flange and a measured 2.50-inch axle offset. The application table lists a 1990 Lincoln Town Car, but the manufacturer does not currently confirm that model application. Do not order for a Town Car by year/model alone; verify the housing-end drawing, bearing retainer and offset first. Check axle-flange diameter, wheel seating, wheel profile and EPB motor clearance through suspension travel. The electronic parking system is for stationary parking hold, not an emergency stop brake. Mounting brackets must allow both service and parking calipers to clear the body and suspension. Use the complete application table below for the individual year, submodel, brake configuration and note attached to each entry.

PMB Performance has over 20 years of experience working with parts and fitment details. Provide the actual brake hardware, mounting dimensions and wheel measurements when requesting help with this conversion.

Manufacturer documentation: Installation instructions; Technical bulletin.

Manufacturer Warning

Applicable to brake pads only: Wilwood warns of exposure to arsenic, cadmium, hexavalent chromium compounds, lead, nickel, cobalt and antimony trioxide, chemicals known to California to cause cancer or reproductive harm. More information: P65Warnings.ca.gov.