Wilwood Rear Red 12.88-Inch FNSL4R Brake & EPB Kit — GM Six-Lug 4x4 (1971–1991), SRP Rotors

The red SRP package equips a matching GM 2.46-inch-offset rear axle with Superlite brakes and EPB hardware. Its 12.88-inch Spec-37 rotors use the six-lug pattern, with BP-10 pads supplied for the radial-mount calipers. The manufacturer is Wilwood Engineering, founded by Bill Wood in 1977 and based in Camarillo, California. It designs and manufactures disc brake components and complete systems, from calipers and brake rotors to valves, master cylinders, fittings and brake lines. Motorsport, street-performance and specialized installations each require those components to be matched to the complete brake system.

Technical Details

• Manufacturer part number: 140-18161-DR
• Service calipers: Forged Narrow Superlite 4R; 4 pistons; radial mount; Red Powder Coat
• Brake rotors: 12.88 x 1.10 inches; Spec-37 Iron; SRP Drilled & Slotted; vented construction
• Pads: BP-10; piston material: Stainless
• Caliper body material: Forged aluminum
• Hydraulic inlet: 1/8-27 NPT
• Rotor/hat wheel-stud clearance pattern(s): 6 x 5.5 in; 6 x 139.7 mm; match the installed hub/axle pattern
• Housing/flange application: K5 Blazer / K10
• Required axle offset: 2.46 in; 62.48 mm
• Parking equipment: separate electric calipers, controller and harness included
• Hydraulic brake hoses: not included; select the correct application-specific lines/fittings
• Wheel clearance: 17-inch wheels may fit; verify the manufacturer’s complete caliper/rotor template for the installed wheel
• Supplied as one kit with mounting hardware; spindles, hubs, master cylinder and booster are not included

Fitment & Compatibility

The Superlite/EPB installation is for a measured 2.46-inch-offset GM six-lug rear axle using the documented flange. Read the individual 1971–1991 application entries for K-series pickups/Suburbans, Blazer/K5 Blazer and Jimmy. Check clearance for both the four-piston service caliper and the electric parking caliper around the 12.88-inch rotor.

DS1676 specifies a 3.55-inch axle center register, a 6 x 5.5-inch lug pattern and a flange no larger than 7.05 inches with a 0.050-inch x 45-degree chamfer. Plan the separate hydraulic line purchase and the routing of the included EPB harness before removing the original brakes.

Confirm the applicable vehicle entry and all numbered notes in the fitment table below.

The electric parking brake is for stationary parking, not an emergency-stop brake. Applying it while the vehicle is moving can lock the rear wheels and cause a skid. Follow the wiring and holding-test procedures in the manufacturer’s instructions.

Manufacturer Resources

• Exact 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.

With over 20 years of parts and fitment experience, PMB Performance can help review the intended brake installation. Provide your VIN, wheel measurements and any modified axle or spindle details when asking about compatibility.

Vehicle Applications

Application Notes

1. Line kit included (manufacturer): None