Wilwood front Forged Narrow Superlite 6R kit components for GM K-Series/Blazer/Jimmy 6-Lug 4x4, black calipers and 12.88-inch gt slotted rotors
Wilwood front Forged Narrow Superlite 6R assembly for GM K-Series/Blazer/Jimmy 6-Lug 4x4, black caliper and 12.88-inch gt slotted rotor
Wilwood front Forged Narrow Superlite 6R kit components for GM K-Series/Blazer/Jimmy 6-Lug 4x4, black calipers and 12.88-inch gt slotted rotors
Wilwood front Forged Narrow Superlite 6R assembly for GM K-Series/Blazer/Jimmy 6-Lug 4x4, black caliper and 12.88-inch gt slotted rotor

Wilwood Front Black 12.88-Inch GT Brake Kit — FNSL6R for GM Six-Lug 4x4 (1971–1991)

SKU: 140-18155

$2,425.23 Sale
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Fitment questions?

Call (855) 786-7101 or text (801) 304-3141. We check fitment by VIN.

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Product details

This black FNSL6R front package uses 12.88-inch GT-slotted rotors for the listed GM six-lug 4x4 applications. Wilwood’s current kit page and DS1671 disagree on the supplied GT rotor thickness, so the rotor pair must be confirmed before ordering or selecting replacement components. Wilwood Engineering’s disc brake systems and components serve motorsport, street-performance and specialized applications. Bill Wood founded the company in 1977; it is based in Camarillo, California. Wilwood designs and manufactures brake rotors and calipers as well as master cylinders, valves, brake lines and fittings. Selecting compatible components is essential to the complete system.

Technical Details

  • Manufacturer part number: 140-18155
  • Service calipers: Forged Narrow Superlite 6R; 6 pistons; radial mount; Black Powder Coat
  • Brake rotors: 12.88 inches diameter; supplied GT rotor thickness requires manufacturer confirmation; Spec-37 Iron; GT Slotted; vented construction
  • Pads: BP-10; piston material: Stainless
  • Caliper body material: Forged aluminum
  • Hydraulic inlet: 1/8-27 NPT
  • Rotor/hat wheel-stud clearance pattern(s): 6 x 5.5 in; 6 x 139.7 mm; match the installed hub/axle pattern
  • Hydraulic brake hoses: not included; select the correct application-specific lines/fittings
  • Wheel clearance: 17-inch wheels may fit; verify the manufacturer’s complete caliper/rotor template for the installed wheel
  • Supplied as one kit with mounting hardware; spindles, hubs, master cylinder and booster are not included

Fitment & Compatibility

Select this 12.88-inch Superlite conversion by the installed six-lug front hub and the exact GM 4x4 listing. The supported group spans specific 1971–1991 K-series pickups/Suburbans, Blazer/K5 Blazer and Jimmy versions, with no blanket coverage across the entire date range. Verify rotor and caliper clearance using the installation drawing.

DS1671 requires hub stud-hole preparation. Hydraulic planning is also essential: Wilwood specifies a recommended 15/16-inch master cylinder when retaining the factory pedal and vacuum booster, rather than the 1.12-inch OE bore that produces very high pedal effort. Where rear drums remain, follow the recommendation for a 10-pound residual valve plus a proportioning valve in their circuit. Hoses are not supplied.

Use the fitment table below to confirm the exact year, model, trim and installation notes.

Manufacturer Resources

WARNING: This product can expose you to chemicals including Arsenic, Cadmium, Chromium (Hexavalent compounds), Lead, Nickel, Cobalt and Antimony Trioxide which are known to the State of California to cause cancer or other reproductive harm. For more information go to www.p65warnings.ca.gov.

With over 20 years of parts and fitment experience, PMB Performance can help review the intended brake installation. Provide your VIN, wheel measurements and any modified axle or spindle details when asking about compatibility.

Vehicle Applications

Years Make Model Model option Front brakes Rear brakes Kit application Notes
1971-1974, 1987-1991 Chevrolet Blazer 4 x 4 Disc Drum Front Kit 1, 2, 3, 4, 5
1971-1991 GMC Jimmy 4 x 4 Disc Drum Front Kit 1, 2, 3, 4, 5
1971-1974 GMC K15/K1500 Pickup 4 x 4 Disc Drum Front Kit 1, 2, 3, 4, 5
1971-1974 GMC K15/K1500 Suburban 4 x 4 Disc Drum Front Kit 1, 2, 3, 4, 5
1975-1986 Chevrolet K10 4 x 4 Disc Drum Front Kit 1, 2, 3, 4, 5
1975-1986 Chevrolet K10 Suburban 4 x 4 Disc Drum Front Kit 1, 2, 3, 4, 5
1975-1986 Chevrolet K5 Blazer 4 x 4 Disc Drum Front Kit 1, 2, 3, 4, 5
1975-1978 GMC K15 4 x 4 Disc Drum Front Kit 1, 2, 3, 4, 5
1975-1978 GMC K15 Suburban 4 x 4 Disc Drum Front Kit 1, 2, 3, 4, 5
1979-1986 GMC K1500 4 x 4 Disc Drum Front Kit 1, 2, 3, 4, 5
1979 GMC K1500 Suburban 4 x 4 Disc Drum Front Kit 1, 2, 3, 4, 5
1980-1986 GMC K1500 Suburban 4 x 4 Disc Drum Front Kit 1, 2, 3, 4, 5

Application Notes

  1. Caution: A 15/16” bore master cylinder is recommended for proper brake function when installing this brake kit with the factory brake pedal and vacuum booster.
  2. Wilwood offers a 15/16” bore tandem master cylinder suitable for this application, p/n 260-18184
  3. Using the OE 1.12” bore master cylinder is not recommended and will require very high pedal effort to stop the vehicle.
  4. Line kit included (manufacturer): None
  5. Front line-kit reference: 220-18356