Brake hardware is the small stuff around the pads, shoes, and caliper that nobody thinks about until it fails: clips, shims, springs, pins, boots, and the caliper slide hardware that lets everything move the way it was designed to. None of it is expensive and none of it lasts forever. The short answer is that most of it should come out and go back in new every time you do a brake job, whether it looks worn or not, because heat cycling and corrosion damage it in ways you cannot see by eye.
This page walks through what each piece of hardware actually does, the specific signs that it has failed, and what a tech replaces versus cleans and reuses on a typical disc or drum brake service.
What Counts as Brake Hardware
On a disc brake, hardware means the abutment clips (also called pad clips) that sit on the caliper bracket lands and give the pads a clean, consistent surface to ride against, the anti-rattle clips or springs that stop the pad from moving around inside the bracket, the shims bonded or clipped to the back of the pad to damp noise, and the caliper slide pins, bushings, and rubber boots that let the caliper float back and forth as the pads wear. On a drum brake, hardware means the hold-down springs and pins that pin the shoes to the backing plate, the return springs that pull the shoes away from the drum when you release the pedal, and the self-adjuster spring and lever that take up slack as the linings wear. A hardware kit matched to the vehicle bundles all of it so nothing gets forgotten; see what's in a brake hardware kit for a part-by-part breakdown.
Disc Brake Hardware: Abutment Clips, Anti-Rattle Clips, and Shims
Abutment clips take the brunt of the pad's movement every time the brakes are applied and released, and that repeated flexing causes metal fatigue that is not visible from the outside. Trade-press brake techs are blunt about this one: replace the abutment clips with every pad job regardless of how they look, because leftover rust on the bracket lands alone can keep a new clip from seating correctly, and a clip with hidden fatigue damage lets the pad wear unevenly and can contribute to a comeback for noise. Anti-rattle clips and springs go through the same heating and cooling cycles. Once they lose tension the pad is free to move slightly inside the bracket under braking, and that small amount of play shows up as a rattle at low speed, uneven pad wear, pulling to one side, or a rotor that wears a lip where the pad no longer tracks it evenly.
Shims are the part most people skip, and they shouldn't. A shim's whole job is to insulate the pad backing plate from the caliper piston and fingers so the metal-to-metal contact that causes brake squeal is damped out. Shims fail two ways: the bonding or clip that holds them to the pad lets go (called shim migration), or the material itself breaks down from years of moisture and heat soaking into the caliper. Either way the pad is now sitting bare against the hardware, and squeal follows. New pads come with new shims attached for exactly this reason - installing old pads' shims on new pads, or skipping them, reintroduces the noise the shim was there to prevent. For more on this specific part, see what brake pad shims actually do.
Caliper Guide Pins, Boots, and Brackets
The caliper has to slide freely on its guide pins (also called slide pins) so that both pads wear evenly and the caliper doesn't drag after you let off the brake. Rust on the pins, a binding pin, or a swollen and hardened rubber boot will all stop that free movement. A boot that has hardened or torn lets water and road salt reach the pin, and lets the factory lubricant squeeze out, so a cheap, inexpensive boot failing early can eventually seize an entire caliper. That's why a full brake job inspects the boots every time and replaces them whenever they show hardening, cracking, or play, even though the pins themselves might be reusable if they clean up and slide smoothly by hand afterward. Only brake-specific lubricant should go back on the pins; the wrong grease can swell rubber boots and cause the same binding you were trying to fix. The caliper bracket itself takes a similar beating: corrosion builds up in the pad channels (the "lands") where the pads and clips ride, and if that rust is not wire-brushed off before reassembly, it binds the pad and causes the same uneven-wear symptoms as a bad clip. A bracket with guide-pin bores that have worn out-of-round should be replaced rather than reused, since it will let the caliper wobble no matter how good the new pins and boots are. Rusted caliper slides also stop a floating caliper from centering itself over the rotor, which quietly reduces the clamping force actually reaching the pad and can lengthen stopping distance even though the pedal feels normal. Corrosion in general is the common thread through nearly every hardware failure on this page; see how corrosion destroys brake hardware for more detail on why road salt is the real enemy here, not mileage.
Drum Brake Hardware: Hold-Down Springs, Return Springs, and the Adjuster
Rear drum brakes depend on hardware even more than disc brakes do, because the shoes have nothing holding them in position except springs and pins. Each shoe is pinned to the backing plate by a small coil hold-down spring compressed under a retaining pin and cap. When those springs or pins corrode badly enough to break, the loose pieces fall down inside the drum, where they can rattle, scratch the drum's braking surface, or wedge between the shoe and the drum and lock the brake up. The return springs - usually two heavier springs per wheel - are what pull the shoes back away from the drum the instant you release the pedal; once they weaken with age, the shoes stay closer to the drum than they should, which shows up as drag, a hot wheel after a drive, or reduced fuel economy from a brake that is partially riding all the time. The self-adjuster spring and lever take up clearance automatically as the linings wear, and a stuck, broken, or disconnected adjuster is one of the most common reasons a drum brake pedal goes low and feels like it needs pumping.
Because every one of these springs is hidden inside the drum and is cheap compared to the labor of pulling the drum a second time, the standard practice is to replace the full hold-down and return spring set any time the shoes come out, not just the pieces that look obviously corroded. A spring that looks fine on the bench can already be reading well below its original tension after years of heat cycling, and there is no way to measure that by eye.
Signs Your Brake Hardware Needs Attention
Hardware failure rarely announces itself with a dash light. Watch for a clicking, rattling, or clunking noise over bumps or at low speed that disappears under hard braking (loose clips or hold-down hardware), a grinding or scraping noise with no metal-to-metal pad contact (a broken spring or pin loose inside the drum), brake squeal that comes and goes with temperature (a failed or missing shim), a pedal that pulses or a car that pulls to one side under braking (a caliper binding on a corroded slide pin or bracket), uneven pad or shoe wear from side to side or inside to outside, or a wheel that runs noticeably hotter than the others after a drive (a caliper or shoe dragging because a return spring or guide pin has lost its job). Any one of these is worth a brake inspection before it turns into a warped rotor or a scored drum.
What to Replace Together
The table below is the general rule of thumb a shop follows when the pads or shoes come off, not a substitute for a visual inspection - anything already broken, cracked, or badly corroded gets replaced regardless of category.
| Hardware | System | Typical practice |
|---|---|---|
| Abutment and anti-rattle clips | Disc | Replace every pad job, regardless of appearance |
| Pad shims | Disc | Replace every pad job (new pads include new shims) |
| Caliper guide pin boots | Disc | Replace if hardened, cracked, or torn; inspect every service |
| Caliper guide pins | Disc | Clean and relube if straight and smooth; replace if rusted or bent |
| Caliper bracket | Disc | Clean corrosion from pad lands; replace if pin bores are worn out-of-round |
| Hold-down springs and pins | Drum | Replace every shoe job |
| Return springs | Drum | Replace every shoe job |
| Self-adjuster hardware | Drum | Replace if sticking, broken, or seized; lube and reuse if it moves freely |
A full hardware kit sized for the vehicle is the simplest way to get every one of these pieces at once instead of hunting for individual clips and springs; browse brake hardware kits for front and rear disc and drum kits. If the inspection turns up a shim or clip problem specifically, it is worth reading up on what uneven pad wear patterns are telling you before reassembly, and on where brake grease belongs and where it does not, since the wrong lubricant on the wrong part causes some of the same symptoms as skipped hardware.
Need the part? Shop Brake Pads & Kits at Core Brake Parts
Filter by your exact year, make, and model — every part ships from our Circleville, OH warehouse, free over $75.
Shop Brake Pads & Kits →Frequently Asked Questions
Can I reuse brake hardware if it still looks fine?
You can on a few individual pieces, like a caliper guide pin that is still straight, clean, and slides smoothly by hand, or a caliper bracket with light surface corrosion that wire-brushes off completely. But clips, shims, and springs take fatigue damage from heat cycling that does not show up visually, which is why shops replace those as a matter of course rather than inspecting them part by part.
What happens if I skip new hardware and just reuse the old pieces?
The most common result is noise - a rattle from loose clips, a squeal from a missing or degraded shim - but it can also mean uneven pad or shoe wear, a caliper that drags and overheats a wheel, or in a worst case a corroded drum-brake hold-down spring breaking and locking the shoe against the drum.
Does a hardware kit come with everything I need?
A kit matched to the vehicle and axle (front or rear, disc or drum) includes the clips, springs, and pins for that specific application. It typically does not include the caliper guide pins themselves or the brake pads and shoes, which are sold separately.
Why do new pads already come with shims attached?
Because the shim is matched to that specific pad's backing plate and thickness. Reusing an old shim on a new pad, or running without one, reintroduces the metal-to-metal contact the shim exists to prevent, which is the single most common cause of brake squeal after a pad job.
How often does drum brake hardware actually need replacing?
There is no mileage interval for it the way there is for fluid - it gets replaced whenever the shoes are replaced, which on most daily-driven vehicles is every one to two pad replacement cycles on the front axle, since rear drum linings wear slower.
Is corroded hardware a safety issue or just a noise issue?
Both, depending on which piece fails. A loose shim or clip is usually just noise and premature wear. A hold-down spring or pin that breaks and falls inside a drum, or a caliper that seizes on a corroded slide pin, can reduce braking at that wheel or cause pulling, which is a safety issue and should be fixed before driving the vehicle further.
Sources
- Tire Review - 7 Brake Hardware Items, Including Abutment Clips, Shims - abutment clip, anti-rattle clip, caliper guide pin, boot, shim, bracket, and pad separator spring function and replacement guidance.
- Motor Magazine - Brake Shop - caliper guide pin, boot, shim, bracket, and abutment clip wear signs and shop replacement practice.
- Tire Review - Brake Hardware: Economizing Fuel, Comebacks and Parts - rusted caliper slides reducing clamping force, soft-part (boot and bushing) deterioration, and brake-rated lubricant guidance.