Brake pads: how they work, when to change them, and what it costs

How your brakes work

When you press the brake pedal, you aren't stopping the car with your leg alone. A chain of parts multiplies your force many times over:

1. 1The brake servo (a booster behind the pedal) adds force, using vacuum from the engine or an electric pump.
2. 2The master cylinder turns that push into pressure in the brake fluid.
3. 3Brake lines carry the fluid to each wheel. Because fluid can't be compressed, the pressure arrives instantly.
4. 4The caliper at each wheel holds one or more pistons. The fluid pushes them out.
5. 5The pistons press two brake pads against the brake disc, a steel disc that turns with the wheel. The pads squeeze it from both sides.
6. 6Friction turns the car's movement into heat, and the car slows down. That's why brakes get very hot, and why pads slowly wear away.

Disc or drum? Almost all cars have disc brakes at the front. Many smaller cars use drum brakes at the back: instead of pads, two curved brake shoes press outwards inside a drum that turns with the wheel. Shoes do the same job as pads, wear more slowly, and are checked and replaced the same way. In this guide, "rear pads" also covers shoes.

What a brake pad is, and how it wears

A brake pad is a steel backing plate with a block of friction material bonded to it: a mix of fibres, metals and binders made to grip the disc and survive high temperatures. Every time you brake, a very thin layer of that material wears away. That's normal: it's what the pad is for.

A new pad has roughly 10–12 mm of friction material. It should be replaced before it's down to 3 mm. Below that, the pad overheats more easily and grips less, and once it's gone, the steel backing plate cuts into the disc.

Why pads wear out, and why there's no fixed schedule

Unlike oil, pads don't age with time. They wear with every stop, so how long they last depends almost entirely on how and where you drive:

• Number of stops. Town driving means a stop every few hundred metres. On the motorway, you might brake a few times an hour.
• Speed and weight. Stopping from a higher speed or with a heavy car turns more energy into heat and wears more material. SUVs, vans and fully loaded cars wear pads faster.
• Front vs rear. When you brake, the car's weight shifts forward, so the front axle does most of the work. Front pads usually wear out well before the rear ones.
• Hills and towing. Long descents and pulling a trailer mean long periods of braking.
• Driving style. Late, hard braking wears pads much faster than easing off early and letting the engine slow the car.
• A fault. A sticking caliper or a handbrake that doesn't fully release keeps a pad rubbing all the time. A sign: one wheel is much dirtier or hotter than the others after a drive.

When to change them

Your maintenance level doesn't change this: wear parts are replaced when they're worn, not on a schedule. What matters is how you drive. Track2Drive estimates when your pads will reach the limit and asks you to check them before then.

How to check your brake pads

You don't need to be a mechanic to keep an eye on your brakes. Start with the checks that need no tools, and look at the pads themselves when you can.

Without tools, every few weeks

• Listen. A high-pitched squeal every time you brake, or any grinding or scraping, means it's time for a check (see "Which noise is it?" below).
• Feel the pedal. It should feel firm and stop at the same point every time. A pedal that feels soft, spongy or goes further down than usual needs a check straight away.
• Watch the dashboard. A brake pad warning light (usually amber) means a wear sensor has made contact.
• Notice how the car stops. Pulling to one side, a shaking steering wheel or pedal, or needing more distance to stop are all signs to have the brakes looked at.
• Check the brake fluid level under the bonnet (a small translucent reservoir marked MIN and MAX). It drops slowly as pads wear, because the pistons move further out. A level near MIN with no leak is a sign to check the pads, not to top up the fluid.

Looking at the pads through the wheel

On most alloy wheels, you can see the brake through the gaps between the spokes:

1. 1Find the caliper, the metal clamp sitting over the edge of the disc.
2. 2Look for the pad: the dark block between the caliper and the shiny disc, with the steel backing plate behind it.
3. 3Judge the thickness of the friction material (not the backing plate). More than about 3 mm is fine; a new pad is about four times that.
4. 4Use your phone's torch, and take a photo zoomed in if it's hard to see.
5. 5For the front wheels, turn the steering to full lock. That gives you a much better view of the caliper.

Wheels with plastic covers, or that hide the brakes

Many cars have steel wheels with plastic wheel covers (hubcaps), or alloy wheels with closed or narrow spokes. You can't see the brakes through them. Your options:

• Take the wheel cover off. Most are held by clips (sometimes by the wheel bolts): pull evenly around the edge with your fingers. Don't lever it with a screwdriver, which breaks the clips and scratches the cover.
• Look from behind, between the tyre and the suspension, with a torch. Easier at the front with the steering turned.
• Ask at the tyre change. If you switch between summer and winter tyres, or have new tyres fitted, the wheels are off anyway. Ask the fitter to look at the pads and discs and tell you how many millimetres are left. It takes them a minute.
• Ask your workshop at any service or oil change. Pad thickness is part of a normal inspection.

Which noise is it?

Brakes make several different noises, and only some of them mean trouble.

Hybrid and electric cars

Hybrids and electric cars slow down mostly by regenerative braking: the electric motor works as a generator and turns the car's movement back into electricity. The pads are used far less, so they often last much longer than the estimates above.

The flip side is that brakes that are rarely used can corrode. Rust builds up on the discs, and the pads or calipers can stick. Brake specialists recommend having the brakes on a hybrid or EV checked at least once a year, even when the pads still look thick. Braking firmly now and then (when it's safe) also helps keep the discs clean.

Warning signs

• A steady high-pitched squeal when braking: the wear indicator.
• Grinding or scraping: metal on metal.
• The brake pad warning light (usually amber: a circle in brackets with dashed lines). A wear sensor in the pad has made contact. Plan the replacement now.
• A longer or softer pedal, or longer stopping distances.
• The car pulls to one side when braking, or the steering wheel or pedal shakes. This often points to the discs or a sticking caliper.
• A burning smell or smoke from one wheel after driving: a brake that's dragging.

What happens if you don't change them

1. 1Longer stopping distances. Thin pads overheat more easily and grip less, especially in an emergency stop.
2. 2Damaged discs. The steel backing plate cuts grooves into the disc. A pad change of about €130 turns into pads and discs for about €400 (EU average).
3. 3Caliper damage. With the pad gone, the piston extends too far and can stick or leak. That adds a caliper to the bill.
4. 4Brake fade or failure. Overheated, worn brakes can lose most of their stopping power on a long downhill or in an emergency stop.
5. 5A failed inspection. Worn brakes fail the roadworthiness test (ITV, MOT, TÜV, contrôle technique).

Why not just follow the manual, or wait for the warning light?

• Manuals say "inspect", not "replace". Most service schedules list "check brake pads and discs" at each service, but services can be one or two years and up to 30,000 km apart. In town, a set of front pads can wear out in between.
• The warning comes late, and not everywhere. Wear warnings are designed for the very end of the pad's life, usually at about 2 mm. Depending on the car, there are only one or two sensors, and many cars have just the squeal tab, which is easy to miss with the radio on.
• The warning doesn't give you time to plan. By the time it lights up, you need a workshop soon, not in a few months.

How to make your brake pads last longer

• Look ahead. Lift off the accelerator early when you see a red light or a queue, and let the car roll. Every stop you avoid saves pad material and fuel.
• Use the engine to slow down. In a manual, stay in gear while slowing; in an automatic or EV, the car does this for you.
• On long descents, use a lower gear and brake firmly in short bursts rather than lightly all the way down. Riding the brakes overheats them and can cause brake fade: a sudden, temporary loss of braking power.
• Don't rest your foot on the pedal. Even light pressure keeps the pads rubbing.
• Carry less weight. Remove heavy things you don't need from the boot.

How brake pads are replaced

1. 1Raise the car safely on axle stands and remove the wheels. Always do both sides of the same axle.
2. 2Remove the caliper (or its guide bolts) and take out the old pads.
3. 3Check the disc thickness against the minimum stamped on it, and check the caliper for leaks and free movement.
4. 4Push the piston back with a piston tool. On many cars with an electric parking brake, the rear pistons must be retracted with a diagnostic tool first. Forcing them can damage the motor.
5. 5Clean the caliper bracket, fit the new pads (and new wear sensors if fitted), and refit the caliper, tightening the bolts to the specified torque.
6. 6Pump the brake pedal until it's firm before driving, then check the brake fluid level.
7. 7Bed in the new pads: about ten moderate stops from 50 to 10 km/h, with a short pause between them. Avoid hard braking for the first 200 km.

At a workshop, this takes about an hour per axle, a little longer at the rear on cars with an electric parking brake.

How much new brake pads cost

For a typical family car (Golf, Clio or Focus size), the parts cost about the same everywhere: around €48 for a set of front pads and €65 for rear pads or shoes. That's also what you pay if you do it yourself. What changes between countries is the labour: about 1.2 hours for the front and 1.8 hours for the rear. Figures are estimates for an independent workshop, VAT included, for both sides of one axle.

Questions people ask