Wilwood Yellow XRS4R Caliper with 3.00-Square-Inch Piston Area and 0.81-Inch Rotor Channel

Yellow powder coat is the finish on this four-piston Wilwood XRS4R brake caliper. Behind that finish, a forged aluminum body carries stainless pistons and a radial attachment for 0.81-inch nominal rotor-width systems; the color does not change those dimensions. Bill Wood established Wilwood Engineering in 1977. Based in Camarillo, California, the company designs and manufactures disc brake systems for motorsport, street-performance and specialized use, including calipers, brake rotors, master cylinders, valves, fittings and brake lines.

Technical Details

• Manufacturer part number: 120-17203-Y. Type: Forged XRS4R Radial Mount caliper.
• Hydraulic inlet thread: 1/8-27 NPT. Match the fitting thread and sealing arrangement to the brake hose.
• 5.98-inch-center radial attachment, universal orientation. 0.39-inch holes; 1.45-inch mounting height.
• 4-piston hydraulic layout with 1.38/1.38-inch bores and 3.00 sq in of effective area; piston type: stainless steel.
• Nominal rotor width 0.81 inch; compatible width range 0.75–0.84 inch. Rotor diameter specification: 11.75–14.00 inches.
• Yellow Powder Coat finish on a forged aluminum body.
• Piston dust boots: no.
• Compatible pad profile 10416; confirm thickness and compound for the installation.
• Caliper component weight: approximately 4.9 lb.
• Component: one individual hydraulic brake caliper. Select the mating rotor, pads, mounting hardware and line connection to suit the complete brake assembly.

Fitment & Compatibility

Compare the 5.98-inch center spacing with the installed bracket and check that its offset aligns the pad sweep. This is an individual hydraulic caliper, so the rotor, plumbing and mounting arrangement need to be selected as a complete system.

For help matching this caliper, contact PMB Performance with the brake-package details and rotor measurements. Our team has more than 20 years of experience with brake parts and fitment.