Black Wilwood XRS4R GT Slotted Kit for Big Ford New Style 2.50-inch Offset — 12.88-inch Rear Disc and Electric Parking Brakes

This 12.88-inch Big Ford rear kit combines black XRS4R hydraulic calipers with separate electric parking calipers. GT slotted discs and BP-10 pads provide service braking, while the included control unit, switch and harness operate the parking system without mechanical cables. Wilwood Engineering, based in Camarillo, California, has designed and manufactured disc brake systems since its founding by Bill Wood in 1977. The range spans calipers, brake rotors, master cylinders, valves, fittings and brake lines for motorsport, street-performance and specialized applications.

Technical Details

Calipers and pads

• Calipers: XRS4R; 4 pistons
• Caliper finish: Black Powder Coat
• Body construction: Forged aluminum
• Pistons: stainless
• Mounting: radial
• Hydraulic inlet: 1/8-27 NPT
• Included pad compound: BP-10
• Listed piston bore sizes: 1.12 / 1.12 in

Kit contents and separate parts

• Manufacturer part number: 140-18295
• Supply: one brake kit; components for both sides of the axle
• Mounting hardware: included
• Hubs: not included
• Spindles, master cylinder and brake booster: not included
• Brake flexlines: not included
• Axle housing flange: Big Ford New Style
• Required axle/hub offset: 2.50 in; 63.5 mm
• Electric parking calipers, switch with pigtail, universal harness and control unit: included

Installation documents

• Installation instructions
• Technical bulletin

Rotors and mounting dimensions

• Rotors: 12.88 in; 327.15 mm diameter x 1.10 in; 27.94 mm thick; vented Spec-37 Iron
• Friction faces: GT Slotted
• Rotor coating/finish: Black Electro Coat
• Internal vanes: 48 curved
• Hats: Aluminum; Black E-Coat; 2.035-inch hat offset
• Rotor/hat wheel-stud clearance patterns: 5 x 4.5 in; 5 x 114.3 mm; 5 x 4.75 in; 5 x 120.65 mm; 5 x 5 in; 5 x 127 mm
• Stud specification: 1/2-inch wheel studs (hat clearance; verify existing axle studs)

Fitment & Compatibility

For Big Ford New Style rear axle flanges with the specified 2.50-inch offset. Confirm bearing diameter, axle register and flange bolt spacing with the linked worksheet, including on the listed 1990 Lincoln Town Car rear-drum application. This 12.88-inch version supplies separate electric parking calipers and their controller, switch and universal harness. Route and mount the electrical system as the instructions specify. It provides parking restraint, not emergency braking while the vehicle is moving. Purchase the service-brake flexlines separately and check the wheel template. Consult the fitment table below for the individual year, model and equipment details. Nominal minimum wheel diameter: 17 in; 431.8 mm. The linked wheel-clearance diagram must confirm barrel and spoke clearance; wheel diameter alone does not guarantee fit.

WARNING: This product can expose you to chemicals including Arsenic, Cadmium, Chromium (Hexavalent compounds), Lead, Nickel, Cobalt and Antimony Trioxide which are known to the State of California to cause cancer or other reproductive harm. For more information go to www.p65warnings.ca.gov.

Our team at PMB Performance draws on 20+ years of brake and restoration work. We can help you review the application requirements before you assemble the system.

Vehicle Applications

Application Notes

1. Line kit included (manufacturer): None