Wilwood left GN6R type iii anodized caliper, 1.38-inch rotor width, 1.75/1.38/1.38-inch bores; Thermlock piston specification: angled logo side and open pad channel

Wilwood Grand National GN6R Caliper with Thermlock Pistons, Left Type III Anodized, 1.38-Inch-wide Rotor

SKU: 120-13949

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Product details

Choose this left-hand Wilwood Grand National GN6R when the installation calls for 1.75/1.38/1.38-inch pistons and 1.38-inch rotor width. The Type III anodized 6-piston body uses a 7.09-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.

The six-piston GN6R uses radial attachment, a removable center bridge and type 7520 pads. Matching bracket kits adapt the caliper to earlier Grand National mounting layouts; the 7.09-inch radial centers are not the bracket-to-spindle spacing.

Technical Details

  • Manufacturer part number: 120-13949
  • Component: Wilwood Grand National GN6R; one caliper
  • Body and finish: Forged aluminum; Type III anodized
  • Dust boots: No
  • Piston arrangement: 6 pistons; 1.75/1.38/1.38-inch bores; Thermlock
  • Hydraulic piston area: 5.40 square inches, as specified by Wilwood
  • Mounting: Left hand; Radial; 7.09-inch centers; 0.45-inch mounting holes
  • Mount height: 2.33 inches
  • Fluid inlet: 1/8-27 NPT
  • Pad shape: Wilwood type 7520; compound selected separately
  • Rotor width: 1.38-inch nominal; 1.25–1.38-inch permitted range
  • Rotor diameter range: 12.19–13.06 inches

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.