Renewing brakes: pads, discs and what goes with them

How to recognise wear on pads and discs is covered in a separate guide. This one starts at the point where it is clear that something has to be done, and answers the questions that follow: what is replaced together, which small parts belong with it, which parts make sense and what happens over the first miles after the work.

Brakes are not a component to economise on, but they are not one where you need to overpay either. Both can be read from the quote once you know which items belong on it.

Pads and discs are replaced per axle, never on one wheel alone. New pads grip differently from bedded-in ones, and an axle with different friction on the left and right pulls to one side under braking. That is why a quote always says “front axle” or “rear axle”, not a single wheel.

Which axle falls due first is less clear-cut than the rule of thumb “the front wears faster” suggests. The front does most of the braking work, but stability systems brake individual wheels deliberately, the rear ones included, and on electric and hybrid cars the lightly used discs are more likely to rust than to wear.

The disc has its minimum thickness stamped on it, and below that the question is settled. Above it, it is a matter of condition: scoring, a pronounced lip, rust pitting on the friction surface or a judder you feel through the pedal all argue for new discs, even if the thickness is still sufficient. New pads on an uneven disc only make partial contact at first and take longer to brake fully.

Many workshops change pads and discs together as a matter of course. That is not necessarily profiteering: most of the labour is the same, and a second appointment for the discs costs more later than the discs cost now. Still, ask for the measured thickness and the condition. A workshop that can answer has actually looked.

Pads and discs are the visible part of the job and the part quotes are compared on. Whether the brakes then work quietly and evenly is decided at the points around them, and those cost little in materials and a little time.

A brake job is more than two parts. These items belong to it and like to be missing from cheap quotes:

On cars with an electric parking brake, a motor sits on the rear caliper. Before the pads can be changed, it has to be driven into a service position using the diagnostic tool; forcing the piston back damages the motor's gearing.

For the owner that means a rear brake job on such cars is no longer something you do at the weekend with a set of spanners, and a workshop needs the right equipment. Ask about it when you request the work, and make sure the parking brake has been recalibrated afterwards — a warning light after the job is a reason to go straight back.

In Europe, replacement pads and discs need approval under UN ECE Regulation 90, which is shown on the packaging. It ensures the part stays close to the original in friction and behaviour. A part without this marking does not belong on the car, however cheap it is.

Within approved parts there are differences you can feel: pads that make less dust but bite a little later; sporty compounds that squeal when cold; coated discs that do not rust on the surfaces that are not swept. For everyday driving, quality close to the original is the right choice. More on the tiers from genuine to aftermarket is in the guide on parts quality.

New pads and discs have to adapt to each other. During this phase the brakes are noticeably weaker than usual, and that is normal. The parts makers describe on the packaging how to bed them in; as a rule that means driving with anticipation over the first miles, several moderate stops rather than an emergency stop, and letting the brakes cool in between.

What is not normal: pulling to one side, a judder in the pedal after a few days, or a noise that does not go away. That belongs back at the workshop, and at the one that did the job — it is responsible for it.

On older cars without an electric parking brake, changing pads is a job practised home mechanics do themselves. It calls for secure support on axle stands, the right tools, a torque wrench and the knowledge of how to reset the piston and lubricate the guides. If you lack any of those, the brakes are not the place to learn.

Brakes are the component where a mistake leaves no second attempt. For most owners the workshop is therefore the right choice — not because the work is complicated, but because someone there answers for the result, and a mistake gets noticed before the road notices it.

A comparable quote lists, per axle, the parts with their maker, the labour time and the ancillary items. Anyone putting two quotes side by side checks first whether both contain the same things: discs or not, sensors, brake fluid, service mode for the parking brake. Only then is it worth comparing the totals.

Through Carvexia you can find businesses that offer brake service and send a booking request with the car, the symptom and a request for a written quote. The request is not yet an appointment: the workshop confirms, proposes another date or declines, and each of those answers arrives by email.