Washer .391 ID x .625 OD .063 Thk

The Washer .391 ID x .625 OD .063 Thk from Wilwood is a precision flat washer engineered for high-performance automotive brake and suspension applications. As a mechanic working on modified vehicles, you'll recognize this component as essential hardware in brake caliper assemblies, rotor mounting systems, and suspension geometry adjustments. This zinc-plated steel washer distributes fastener loads evenly across component surfaces, preventing surface damage and ensuring consistent clamping force—critical when working with lightweight aluminum or composite brake parts that demand load spreading.

Manufactured to exacting dimensional tolerances, this washer features a 0.391-inch inner diameter, 0.625-inch outer diameter, and 0.063-inch thickness—specifications that match Wilwood's OEM brake hardware standards. The zinc-plated finish provides corrosion resistance essential for underbody components exposed to moisture and road salt, while maintaining consistent friction characteristics during assembly. Steel construction delivers the rigidity needed to maintain load distribution without deformation during torque application, a critical factor when reassembling brake calipers or suspension components where uneven pressure could cause binding or pad drag.

This washer is ideal for builders and technicians upgrading to Wilwood brake systems on street rods, performance trucks, and track vehicles where OEM hardware compatibility matters. Installation is straightforward—simply slide onto fasteners before tightening caliper bolts, brake line banjo fittings, or suspension pivot points. The individual washer format allows for custom quantities and replacement of damaged units without purchasing complete assemblies, making it an economical choice for brake rebuilds and suspension service work.