How to choose brake pads
Ceramic, semi-metallic, and organic pads are different friction mixes, not a ranking from cheap to good. Pick the mix for the vehicle and the way it is driven, then match the part number to the axle.
What the pad is doing
Brake pads are the blocks that press on the rotors. When you push the pedal, fluid pressure moves the caliper pistons, the pads clamp the rotor, and the car slows down. Most of that work happens at the front axle. The rear pads, or rear shoes on a drum, do less of the stopping and often use a different part number.
The compound is the recipe of the friction material. It changes cold pedal feel, behavior after a long grade, wheel dust, and how fast the pad wears. It does not change the shape of the backing plate. A ceramic pad in the wrong shape is still the wrong part. Start with fitment, then choose among organic, semi-metallic, and ceramic street pads.
Organic pads
Organic pads, often labeled NAO for non-asbestos organic, use fibers, fillers, and resins rather than a large share of metal. On a normal commute they tend to be quiet and gentle on rotors. Pedal feel is usually progressive, which a lot of drivers prefer in traffic. Dust is typically moderate.
The limit is heat. Repeated hard stops, a mountain grade, or a heavier vehicle can push an organic pad past the temperature it handles well. The pedal can get longer, and stopping power can fade until the brakes cool. Organic pads also tend to wear faster than a harder compound. On a light car used for ordinary driving, organic is a reasonable quiet choice when the shape matches that axle.
Semi-metallic pads
Semi-metallic pads mix metal fiber into the friction material. The metal helps carry heat away from the surface and gives the pad more bite when the brakes are already hot. Trucks, vehicles that tow, and cars that see steep roads often leave the factory with a semi-metallic or low-metallic pad on the front, where the heat is.
Those traits have costs. Semi-metallic pads can squeal when cold or when the clips are dry, and they can wear a thin or rough rotor faster. The dust is often darker. That is a firmer, sometimes noisier brake, not automatically a defective pad. Plan on clean hardware and a rotor that is still thick enough.
Ceramic pads
Ceramic pads use ceramic fibers and other fillers. Many current formulas are also made with little or no copper, because several states limit copper in brake friction material sold for passenger cars. The traits owners usually notice are lighter-colored dust and, on many passenger cars, less noise than a semi-metallic pad.
A ceramic pad can feel slightly less aggressive when cold, then settle once it is warm. It is a common choice for a quiet street car and a clean wheel. It is not automatically the right pad for towing or a heavy truck. A ceramic pad for a compact sedan is a different part from a severe-duty pad for a heavy pickup, even if both boxes say ceramic.
How to choose for your driving
Start with the vehicle, not the slogan on the box. Front and rear pads are often different numbers. A towing package, a performance brake option, or a heavy-duty rotor can take a different pad than the base model of the same year. Use the year, make, model, and engine, and any brake option you can identify from the old pad or a build label. The guide to finding the right part covers VIN and original-equipment numbers. On PartIndex, open the brake line for that vehicle and compare the numbers side by side.
Then match the compound to the work. Ordinary commuting points toward ceramic or organic, if the pad is listed for the vehicle. Towing, mountain roads, a heavier SUV, or brakes that have faded point toward a semi-metallic pad or another compound rated for heat. Use one compound on both sides of an axle. Replace pads as a set, and do not keep a pad that is down to the indicator or the backing plate.
Rotors, hardware, and what else to buy
Pads rarely fail alone. Compare rotor thickness with the minimum stamped on the hat or listed in the service information. A new pad on a rotor that is under the minimum, cracked, or deeply grooved will not fix a pulsation or a noise. Machine a rotor only if it will still be above the minimum afterward. Otherwise replace rotors in pairs.
Many pad sets include new abutment clips and shims. Use them. Clean the bracket where the clips sit. Use a brake-rated lubricant on the sliding points the service information calls for, and keep that grease off the friction surface and off the rotor face. A sticky slide pin makes one pad do the work of two. That feels like a bad compound and wears the set unevenly.
If the caliper piston is seized or the dust boot is torn, a new pad will not move the way it should. Rebuild or replace the caliper, and replace a hose that is cracked or bulging. If you open the hydraulic system, bleed it and use the fluid specification for the vehicle. Brake fluid damages paint, so keep it off the body.
Bedding and noise
New pads need a film of material on the rotor. Follow the maker’s bed-in steps if they are printed on the box. A typical street procedure is a series of medium stops from a moderate speed, with time to cool between them, without sitting on the pedal at a full stop. Holding the pedal while stopped can print a spot onto the rotor and bring a shudder back.
Noise after a pad job is often the hardware. Missing shims, bent clips, and a rotor filmed with oil from your hands are common. So is a wear indicator touching because the pad went on the wrong side. The indicator usually belongs at the trailing edge, but the service information for that caliper is the source to check, not a guess.
Brakes are a safety system. If the pedal sinks, the car pulls hard, you hear grinding, or a brake warning lamp stays on, do not keep driving it as a normal trip. Grinding often means the backing plate is cutting the rotor. Support the car on jack stands, chock the wheels that stay down, and do not rely on a jack alone. Tighten caliper bolts and wheel nuts to the specification for that vehicle. If you cannot bleed the brakes or measure a rotor, have that part done by a shop.
After the job, check the fluid level. Pushing pistons back into the calipers raises the level in the master cylinder, and an overfilled reservoir can spill. Take a short drive in a quiet area before you merge into fast traffic, and confirm the pedal is high and firm.