Wilwood Forged Dynalite Internal Caliper, Red, 1.38-Inch Bores and 3.00-Sq.-In. Area

This Wilwood Forged Dynalite Internal is a 4-piston brake caliper with a red finish for a nominally 0.81-inch-wide rotor. Its 5.25-inch lug mounting centers and 1.38-inch piston bores must match the brake assembly. Wilwood Engineering was founded by Bill Wood in 1977 and is based in Camarillo, California. The company makes disc brake systems and components, including calipers, rotors, master cylinders, valves, fittings and brake lines for motorsport, street-performance and specialized applications.

Technical Details

• Manufacturer part number: 120-13839-RD
• Component: Wilwood Forged Dynalite Internal; one caliper
• Rotor width: 0.81-inch nominal; 0.75–0.83-inch permitted range
• Rotor diameter range: 10.00–13.06 inches
• Mounting: universal side configuration; Lug; 5.25-inch centers; 0.39-inch mounting holes
• Mount height: 2.03 inches
• Piston arrangement: 4 pistons; 1.38-inch bores; stainless steel
• Hydraulic piston area: 3.00 square inches, as specified by Wilwood
• Pad shape: Wilwood type 7112; compound selected separately
• Body and finish: Forged aluminum; Red Powder Coat
• Dust boots: No
• Fluid inlet: 1/8-27 NPT

This four-piston Dynalite uses internal fluid transfer in a spacerless body. Its 5.25-inch mounting pattern is only one compatibility dimension: rotor position, body clearance and hydraulic area also need to agree.

Fitment & Compatibility

Check mounting-center spacing and bracket offset together, then confirm the pad sits fully on the rotor friction surface. Piston area must suit the master cylinder and front-to-rear brake 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.