Wilwood Rear Four-Piston GT Parking Brake Package, Red, GM G-Body Flange at 2.62-Inch Offset

Wilwood configures this rear Superlite 4R kit around 12.88 × 1.10-inch rotors for GM G-Body Axle Flange. The selected red calipers use 4 service pistons each; matching the factory or specified conversion hardware is essential to the complete installation. Camarillo, California is home to Wilwood Engineering, founded in 1977 by Bill Wood. The company designs and manufactures disc-brake systems for motorsport, street-performance and specialized applications. Calipers, brake rotors, master cylinders, valves, fittings and brake lines form a range whose individual components must match the complete braking system.

Technical Details

• Manufacturer part number: 140-17658-R; supplied as an axle kit.
• Hydraulic sizing: cataloged bore sizes 1.12, 1.12 inches; piston area 1.98 square inches; inlet 1/8-27 NPT.
• Wheel envelope: 17-inch minimum nominal wheel diameter; verify the entire wheel-clearance drawing, including spoke and barrel shape.
• Hardware and retained components: Mounting hardware supplied; existing wheel hubs retained; spindles, master cylinder and brake booster are not included.
• Parking brake: Internal shoe parking brake supplied; cables, cable hardware and adapters are separate.
• Hydraulic lines: Hydraulic flexlines and fittings are not included; select compatible lines for the complete installation.
• Service calipers: Forged Narrow Superlite 4R; 4 pistons per caliper; Red Powder Coat; radial mounting; stainless pistons.
• Supplied friction pads: BP-10 compound; match operating conditions to the intended use.
• Housing-flange requirement: G-Body flange; 2.62-inch axle offset, measured using the manufacturer worksheet.
• Brake rotor size: 12.88-inch outside diameter × 1.10-inch thickness; vented friction section.
• Machining prerequisite: Housing-flange material removal and two drilled holes required; follow the specific drawing and arrange qualified machine-shop work.
• Rotor specification: Material: Spec-37 Iron; Type: GT 48 Curved Vane; Style: GT Slotted; Surface Finish: Black Electro Coat.
• Rotor hats: Aluminum parking brake hat - standard; Black E-Coat; hat offset 1.950 inches. Hat offset is distinct from axle offset.
• 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.

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.

PMB Performance brings more than 20 years of parts experience to fitment questions. Send your VIN and details of the installed brakes so we can help check the application.

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.