The little clips and springs in a brake hardware kit look minor, but each has a specific job in keeping brakes quiet and even-wearing. Knowing the types helps you understand why replacing them matters. Here are the main brake hardware pieces.
Abutment (anti-rattle) clips
Abutment clips snap onto the caliper bracket where the pad ears rest. They give the pad a clean, spring-loaded surface to sit and slide on, so it moves freely as it applies and releases and does not rattle. Rust building behind old clips is a top cause of sticking pads and noise - part of the hardware kit.
Anti-rattle springs
The anti-rattle spring puts constant light tension on the pad to hold it snug against the caliper or bracket so it cannot vibrate over bumps; without it you get a rattle - see brake pad gap noise.
Shims
Damping shims attach to the back of the pad to absorb the high-frequency vibration between pad and caliper piston that causes squeal. They are a key quiet-brake component that cheap pads sometimes skip.
Replace them with the pads
All of these should be replaced with every pad change - most quality pad sets include new hardware; see when to replace brake hardware. Reusing tired clips and shims is the number-one reason a fresh brake job is noisy. Fit quality pads with a complete hardware kit.