Brake pads and discs: what’s the difference?

Brake jobs are often quoted as “pads and discs”, and it isn’t always obvious whether you need both. Here’s what each part does and what to ask.

What they are

The disc (also called a rotor) is the metal disc that spins with your wheel. The pads are blocks of friction material that the caliper squeezes against the disc when you press the brake pedal. The friction slows the car.

Which one wears faster

Pads wear faster, because they’re designed to be the part that gives way. Discs wear more slowly but they do wear, and each has a minimum thickness set by the manufacturer. Many garages check the discs whenever pads are changed. Whether to replace both depends on their condition, so it’s worth asking for the measurements.

Warning signs

• A high-pitched squeal when braking.
• A grinding noise, which can mean the pad material has worn away.
• Vibration through the pedal or steering wheel when braking.
• The car pulling to one side when you brake.
• Longer stopping distances, or a brake warning light.

A soft or spongy pedal can point to a different problem, such as air or fluid in the system, so get that checked promptly.

Front, rear or both?

The front brakes do most of the work of stopping the car, so they usually wear faster. Parts are normally replaced in pairs across an axle (both left and right), so the car brakes evenly.

Pads only, discs only, or both?

Ask the garage:

• How thick are the discs now, compared with the minimum?
• Are they scored, warped or showing a raised lip at the edge?
• If you’re only changing the pads, will they bed in properly on the old discs?

Budget, branded and premium parts

Brake parts come in a range of materials and quality. Differences can include how long they last, how much noise and dust they produce, and how they feel when you brake. The right choice depends on your car and how you drive, and whatever you pick should be listed as suitable for your exact vehicle.

What else might the job need?

Ask what the quote includes. Some jobs also need wear sensors, fitting kits or clips, brake fluid, or work on the calipers. A clear quote lists these separately.