1in Rebuild Kit

The Wilwood 1in Rebuild Kit (SKU: WIL260-3883) is a complete OEM-spec seal and component assembly designed for Wilwood master cylinders with a 1-inch bore. This rebuild kit exists to restore hydraulic integrity and brake feel to aging or worn master cylinders without requiring full unit replacement. Mechanics, restoration enthusiasts, and high-performance brake builders rely on rebuild kits to maintain pressure consistency and eliminate sponginess in the pedal—critical for both street and track applications where brake modulation directly impacts safety and stopping power.

The kit includes all sealing surfaces necessary for complete internal renewal: primary and secondary pistons, o-rings and cup seals, a dust boot to protect against contamination, and a snap ring for secure piston retention. These components are engineered to match OEM friction coefficients and fluid compatibility, ensuring the rebuilt cylinder generates full system pressure without leakage or drift. The 1-inch bore specification indicates this kit suits standard-duty street and dual-purpose brake systems; proper installation requires draining old fluid, careful component cleaning, and light assembly fluid application to avoid seal damage during insertion.

This rebuild kit benefits owners of vehicles equipped with Wilwood master cylinders—common in classic car restorations, custom hot rods, and modern performance builds where aftermarket brake systems deliver superior modulation. Installation is straightforward for technicians familiar with master cylinder disassembly, typically requiring under an hour of labor. Compatibility is limited to Wilwood cylinders with 1-inch bore diameter; verify your existing cylinder specification before ordering. Compact dimensions and lightweight design (0.38 lbs) make this kit easy to stock and ship, ideal for DIY rebuilds or professional shop inventory replenishment.