Wilwood FSL4R 4-Piston Caliper in Type III Anodized, 5.98-Inch Radial Attachment

Choose this Wilwood Forged Superlite 4R when the installation calls for 1.25-inch pistons and 1.25-inch rotor width. The Type III anodized 4-piston body uses a 5.98-inch radial pattern; check its complete geometry before substituting another caliper. Bill Wood founded Wilwood Engineering in 1977. Based in Camarillo, California, Wilwood designs and manufactures disc brake systems and parts for motorsport, street-performance and specialized applications, from calipers and rotors to master cylinders, valves, fittings and brake lines.

Technical Details

• Manufacturer part number: 120-13576
• Mounting: universal side configuration; Radial; 5.98-inch centers; 0.39-inch mounting holes
• Mount height: 1.63 inches
• Rotor width: 1.25-inch nominal; 1.15–1.35-inch permitted range
• Rotor diameter range: 11.75–14.00 inches
• Pad shape: Wilwood type 7420; compound selected separately
• Piston arrangement: 4 pistons; 1.25-inch bores; Thermlock
• Hydraulic piston area: 2.46 square inches, as specified by Wilwood
• Body and finish: Forged aluminum; Type III anodized
• Fluid inlet: 1/8-27 NPT
• Dust boots: No
• Component: Wilwood Forged Superlite 4R; one caliper

Internal fluid passages and radial mounting distinguish this four-piston Superlite. The selected piston design and bore sizes must match the brake balance calculation; they are not interchangeable merely because the mounting centers agree.

Fitment & Compatibility

Plan the caliper installation with the rotor centered in the pad gap. Verify attachment hardware, hose connection and accessible upper bleeders, then confirm the brake system’s hydraulic balance.

This listing covers one caliper. Match the brake pads, rotor, hose and mounting arrangement to the complete brake system.

PMB Performance has over 20 years of brake and parts experience. Send us the caliper specifications, rotor measurements and bracket details if you need help selecting the correct component.