Wilwood Rear Special 12-Bolt Brake Kit, 3.15-Inch Bearings & 2.81-Inch Offset — Black Calipers, 12.88-Inch GT Rotors

This specialty 12-bolt conversion supplies black Superlite calipers and GT-slotted 12.88-inch rotors. It uses the documented 3.15-inch-bearing housing arrangement and supplied retainers, together with internal parking-brake backing plates. Founded in 1977 by Bill Wood and based in Camarillo, California, Wilwood Engineering designs and manufactures disc brake systems and components for motorsport, street-performance and specialized applications. Its range includes calipers, brake rotors, master cylinders, valves, fittings and brake lines, selected to work together within a properly matched brake system.

Technical Details

• Manufacturer part number: 140-9215
• Service calipers: 4-piston Forged Narrow Superlite 4R; Black Powder Coat; radial mounting
• Brake rotors: 12.88 x 1.10 inches; Spec-37 Iron; GT Slotted; vented
• Included pad compound: BP-10; pistons: stainless steel
• Caliper body: Forged aluminum; hydraulic inlet: 1/8-27 NPT
• Rotor surface finish: Black Electro Coat; rotors are not supplied burnished
• Rotor/hat wheel-stud clearance pattern(s): 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; the existing hub/axle pattern is retained
• Hat/rotor stud-hole clearance: 0.520 in; 13.21 mm; this is not a wheel-stud thread designation
• Required axle offset: 2.81 inches; measure from the axle flange to the housing flange as shown in the instructions
• Parking brake: internal drum/shoe assemblies included; cable, clevis and control hardware are separate
• Hydraulic hoses: not included; match the separate lines and fittings to the application
• Kit includes calipers, rotors and mounting hardware; replacement hubs and spindles are not included
• Not included: master cylinder and brake booster
• Wheel clearance: 17-inch wheels may fit; check the complete manufacturer caliper/rotor template
• Quantity: sold as one axle kit

Fitment & Compatibility

For the specialty Chevrolet 12-bolt rear housing with the specified 3.15-inch bearing and 2.81-inch axle offset. This retained-bearing configuration is distinct from a factory C-clip axle. Treat the listed vehicle names as conditional applications: the installed housing flange and bearing arrangement must match DS525.

The supplied bearing retainers are fitted with the parking-brake backing-plate assemblies. Verify the 2.80-inch register/adaptor arrangement and 6.61-inch maximum axle flange with the required chamfer. Hydraulic plumbing and parking-cable hardware are not supplied; select them for the completed vehicle.

Use the fitment table below to confirm the exact model, year, trim and all numbered application notes.

Adjust and test the mechanical parking brake as directed. Cable routing, tension and shoe adjustment affect its holding ability; do not rely on an untested parking brake alone to secure the vehicle on a slope.

Manufacturer Resources

• Wilwood kit specifications and wheel-clearance information
• Installation instructions and component list
• Axle-offset measurement worksheet

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.

PMB Performance brings over 20 years of experience with brake components and fitment details. Send us your VIN together with the installed axle, spindle, brake and wheel specifications if you need help confirming this package.

Vehicle Applications

Application Notes

1. Universal Flexline kits available: 220-7056 (14"), 220-7699 (16") or 220-8307 (18"). Choose correct length for your application.
2. Universal Parking Brake cable kit, may require modifications to cable or vehicle to install.
3. Line kit included (manufacturer): None