Fitment questions?
Call (855) 786-7101 or text (801) 304-3141.
Real people. Real answers.
Product details
Black Superlite 4R calipers provide the hydraulic service braking in this Wilwood rear conversion for GM G-Body Axle Flange. They work with 12.88 × 1.10-inch gt slotted rotors; the vehicle designation must be considered together with the mounting details below. Wilwood Engineering, founded by Bill Wood in 1977, is based in Camarillo, California. Its work covers the design and manufacture of disc-brake systems and components for specialized vehicles, motorsport and street-performance use. The product range includes calipers, brake rotors, master cylinders, valves, fittings and brake lines; compatibility depends on the complete system.
Technical Details
- Manufacturer part number: 140-17658; supplied as an axle kit.
- Rotor/hat mounting-hole pattern: 5 x 4.5 in; 5 x 114.3 mm; 5 x 4.75 in; 5 x 120.65 mm; 5 x 5 in; 5 x 127 mm; cataloged hole clearances 0.520 in; 13.21 mm. These are rotor or hat drillings, not replacement wheel studs. The retained hub or axle determines the vehicle wheel pattern.
- Brake rotor size: 12.88-inch outside diameter × 1.10-inch thickness; vented friction section.
- Rotor hats: Aluminum parking brake hat - standard; Black E-Coat; hat offset 1.950 inches. Hat offset is distinct from axle offset.
- Hydraulic lines: Hydraulic flexlines and fittings are not included; select compatible lines for the complete installation.
- Supplied friction pads: BP-10 compound; match operating conditions to the intended use.
- Hardware and retained components: Mounting hardware supplied; existing wheel hubs retained; spindles, master cylinder and brake booster are not included.
- Service calipers: Forged Narrow Superlite 4R; 4 pistons per caliper; Black Powder Coat; radial mounting; stainless pistons.
- Parking brake: Internal shoe parking brake supplied; cables, cable hardware and adapters are separate.
- Hydraulic sizing: cataloged bore sizes 1.12, 1.12 inches; piston area 1.98 square inches; inlet 1/8-27 NPT.
- Machining prerequisite: Housing-flange material removal and two drilled holes required; follow the specific drawing and arrange qualified machine-shop work.
- Housing-flange requirement: G-Body flange; 2.62-inch axle offset, measured using the manufacturer worksheet.
- Rotor specification: Material: Spec-37 Iron; Type: GT 48 Curved Vane; Style: GT Slotted; Surface Finish: Black Electro Coat.
- Wheel envelope: 17-inch minimum nominal wheel diameter; verify the entire wheel-clearance drawing, including spoke and barrel shape.
Fitment & Compatibility
DS1571 specifies a G-Body housing flange and 2.62-inch axle offset. This conversion requires substantial housing-flange modification, including material removal and drilling two holes; qualified machining should be arranged before disassembly. Check the axle register, stud clearance and complete 17-inch wheel envelope. The internal parking brake needs separately selected cables, cable hardware and adapters; no hydraulic hoses are supplied.
With more than 20 years of parts experience, PMB Performance can help compare your VIN and installed hardware with the required configuration. Include any suspension, wheel or axle changes.
Review Installation instructions, Technical bulletin for the complete installation and clearance requirements.
Manufacturer Warning
Applicable to brake pads only. 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.
