Wilwood 140-18271 FNSL4R/MC4 Rear Big Brake Kit 13.50in Rotor

The Wilwood 140-18271 is a Forged Narrow Superlite 4R (FNSL4R) with MC4 Rear Big Brake Kit featuring oversized 13.50-inch rotors, purpose-built as a high-performance rear disc brake upgrade for the Nissan 240SX (1989–1998). This kit is engineered to pair seamlessly with Wilwood front big brake upgrades, delivering a fully balanced, high-capacity braking system for custom, high-performance, and track-driven builds.

Key Features:

• Forged Narrow Superlite 4R (FNSL4R) four-piston calipers with a forged aluminum body and Type III Mil-Spec hard anodized finish for superior wear, abrasion, and corrosion resistance
• MC4 mechanical auxiliary caliper provides a clean, effective parking brake solution integrated into the big brake system
• 13.50-inch two-piece rotors deliver increased brake leverage and enhanced thermal cooling capacity over stock
• Thermlock pistons reduce heat transfer from pads to caliper, extending service life and improving fade resistance
• Internal damper springs and controlled retraction, high-temperature piston seals ensure consistent pedal feel and height
• BP-10 or BP-20 compound brake pads included for high-performance street and track use
• Caliper piston volumes are matched for full compatibility with the OE master cylinder output and ABS systems
• Also fully compatible with manual brake conversions using appropriately sized master cylinders and balance bar pedals
• Available in multiple caliper finish and rotor design options to complement custom wheel and suspension builds

This rear big brake kit is designed to integrate with wheel, tire, and suspension upgrades common on modified Nissan 240SX S13 and S14 platforms. The FNSL4R/MC4 system replaces the factory rear brake setup with a race-proven, high-capacity solution while retaining OE parking brake functionality, ABS compatibility, and proper front-to-rear brake bias balance.