Wilwood Rear GM Six-Lug 4x4 GT/EPB Package (1971–1991), Red Four-Piston Superlite & 12.88-Inch Rotors

Red FNSL4R calipers and GT-slotted 12.88-inch rotors define this electric-parking rear kit for listed GM 4x4 applications. Confirm the axle dimensions and wheel template before wiring and assembling the supplied EPB system. Calipers, brake rotors, master cylinders, valves, fittings and brake lines are all part of Wilwood Engineering’s range of disc brake systems and components. The Camarillo, California company was founded in 1977 by Bill Wood and designs and manufactures these products for motorsport, street-performance and specialized applications. Compatibility with the complete brake system determines the appropriate component choice.

Technical Details

• Manufacturer part number: 140-18161-R
• Rotor specification: Spec-37 Iron, GT Slotted, vented; 12.88 x 1.10 inches
• Caliper specification: 4-piston Forged Narrow Superlite 4R in Red Powder Coat; radial mount
• Included service pad compound: BP-10; Stainless pistons
• 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.

The table below provides the full application breakdown; match its year, model and brake-configuration details.

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.

Ask PMB Performance to help confirm the configuration before ordering if the vehicle has modified brakes or running gear. We have over 20 years of experience with parts and fitment; a VIN plus the installed component details gives us the best starting point.

Vehicle Applications

Application Notes

1. Line kit included (manufacturer): None