Fitment questions?
Call (855) 786-7101 or text (801) 304-3141. We check fitment by VIN.
Product details
This anodized Wilwood GN4R-ST left brake caliper uses a 7.09-inch radial mount and the 1.25-inch rotor-width configuration. It is sold as one caliper, with its piston and mounting specification selected for the complete brake assembly. Grand National GN4R-ST is a forged four-piston radial caliper with Thermlock insulated pistons. Its special bracket offset and 7520 pad outline require a measured brake assembly. Use the exact nominal rotor width below rather than a general family-width assumption. Founded by Bill Wood in 1977, Wilwood Engineering is based in Camarillo, California. It designs and manufactures disc brake systems and components, including calipers, brake rotors, master cylinders, valves, fittings and brake lines, for motorsport, street-performance and specialized applications. Components must be selected to suit the complete brake system.
Technical Details
- Manufacturer part number: 120-16529
- Component: Grand National GN4R; one individual caliper
- Placement: Left
- Construction and finish: Forged aluminum; Type III Anodize
- Nominal rotor width: 1.25 inches
- Rotor width range: 1.19–1.25 inches
- Rotor diameter range: 12.19–14.00 inches
- Caliper weight reference: 8.0 lb
- Mounting interface: Radial; mounting centers 7.09 inches
- Mounting-hole diameter: 0.45 inches
- Mount height: 2.33 inches
- Hydraulic inlet thread: 1/8-27 NPT
- Pistons: 4; Thermlock insulated; bore dimensions 1.88/1.75 inches
- Hydraulic piston area: 5.18 square inches
- Dust boots: No
- Brake pad shape: 7520; shape number does not specify a friction compound
Fitment & Compatibility
Match the 7.09-inch radial attachment to the existing bracket, then check caliper centering over the 1.25-inch nominal-width rotor. Use the left-hand caliper and keep the bleed arrangement in the specified orientation. The 1/8-27 NPT connection must use the correct fitting and seal. Check the full wheel envelope with the actual bracket and rotor installed.
Wilwood caliper specifications
Contact PMB Performance for a component comparison using the actual caliper, bracket and rotor measurements. Our team has over 20 years of experience with parts and fitment details.
