Wilwood 120-14439-RD Forged Narrow Superlite Dust Seal Disc Brake Caliper - 4R Red

The Wilwood Forged Narrow Superlite 4R Dust Seal Caliper (FNSL4R-DS) represents the latest evolution of Wilwood's proven Superlite caliper series. Featuring an exclusive wiper dust seal, this caliper is engineered for use in environments requiring environmental sealing, delivering "Big Brake" stopping power across a wide range of vehicle applications — even under extreme conditions.

Stress-Flow Forged Aluminum Body

Each caliper body is precision stress-flow forged from premium-grade aluminum alloy billets. This forging process re-aligns the metal's internal grain structure to follow the contour of the caliper body, eliminating the structural weaknesses introduced by straight billet machining. The result is one of the strongest lightweight aluminum caliper bodies available. Computer-generated solid modeling and FEA (Finite Element Analysis) stress analysis were used throughout the design process, with the final assembly starting at just 4.9 pounds.

Key Features:

• Exclusive wiper dust seal for environmental protection in demanding applications
• Stress-flow forged aluminum body for maximum strength and reduced weight (from 4.9 lbs)
• Six-piston differential bore configuration provides balanced pad loading and even wear in sustained high-heat environments
• One-piece stainless steel pistons standard — chosen for low heat transfer and high corrosion resistance
• Thermlock piston upgrade available — multi-part design creates a thermal barrier to reduce heat transfer to seals and fluid
• SRS (Spring-loaded Retention System) bridge plates eliminate pad gouging wear, prevent pad rattle, and dampen harmonic vibrations that cause pad squeal
• Dual two-piece bleed screws (one on each end) with internal fluid crossovers for protection against track debris
• High-temperature square-faced bore seals maximize sealing area and ensure controlled piston retraction on release
• Red anodized finish for a bold, high-performance appearance
• Compatible with the full range of Wilwood brake pad compounds to match any competition or performance driving application

The FNSL4R-DS is a purpose-built performance caliper designed for serious motorsport and high-performance street use. Whether the goal is track-day dominance or spirited street driving, Wilwood's FNSL4R-DS delivers reliable, fade-resistant braking with the durability to handle sustained punishment in the most demanding environments.