How to Replace Brake Pads and When to Call a Professional

Brake pads are one of the few components where the job is genuinely straightforward on some vehicles and genuinely unpleasant on others. The decision to do it yourself comes down to the layout: whether the caliper is a bolt-on type or an integral type, whether the vehicle uses a drum at the rear, and whether you have a torque wrench and a way to hold the vehicle off the ground. Understanding that first saves a lot of wasted effort.

This guide covers when it is reasonable to do the work, the procedure, and the mistakes that shorten the life of the new pads.

Knowing Whether the Job Is Suited to You

A bolt-on caliper is held to the hub by two or three bolts and the pads slide in and out of it. Removing the caliper, exchanging the pads, and refitting is a straightforward job that a competent person with basic tools can do. An integral caliper, where the piston is integral with the caliper body and the whole assembly has to be removed and the pistons retracted with a piston wind-back tool, is significantly more involved, and the piston wind-back is where most home attempts go wrong.

Some vehicles have floating calipers on one axle and fixed on the other, which is common. Drum brakes at the rear are a different job entirely and not one to attempt without experience. And on a vehicle with a retractable parking brake, the caliper has to be wound back to service the caliper, which requires the correct tool for the specific design.

The practical prerequisites are a solid jack or the correct wheel support, a torque wrench for the caliper bolts, a bleed kit if the system will be opened, and somewhere to work with the vehicle supported properly throughout. A hydraulic brake system must never be worked on with the vehicle resting on a jack.

Checking Before Removing Anything

Measure the remaining friction material on every pad before starting, including the inner pad, which is the one most often overlooked because it is harder to see. Where a wear sensor is fitted, check the wire for a frayed end, which indicates the pad has worn past the sensor rather than merely to the depth you measured.

Compare the inner and outer pads. A substantial difference points at a sticking or incorrectly retracting caliper, and if that is not corrected, the new pads will wear out at the same rate. The caliper is covered in more detail in our guide to extending brake pad life, along with the habits that cause uneven wear.

The Procedure

Raise the vehicle, remove a wheel, and inspect the disc and caliper before proceeding. Run a finger around the disc face and along the inner edge. A deep groove means the disc must be machined or replaced, and fitting pads to a badly worn disc produces a pulsing pedal and poor braking that people frequently blame on the new pads. Check the caliper for any weeping of fluid or brake fluid in the caliper area, which is a safety issue.

Remove the caliper bolts, lift the caliper clear, and support it so it does not hang by the hydraulic hose. Never let a caliper hang on the hose, because the hose carries the pressure that moves the piston and it will be damaged. Never cut or bend a brake hose, and never work on the hydraulic system with the engine running, because the pump will move fluid.

Withdraw the old pads and note their orientation, because many are fitted with a chamfer, a wear indicator, or a shim that must face in a specific direction. Clean the caliper body and the pad abutments, because brake dust is abrasive and any that remains behind the new pads causes uneven pressure and squealing. Fit the new shims or anti-squeal strips as specified, and apply a thin film of assembly lubricant or brake grease to the pad backing plate contact points. That last step is what prevents squeal, and it is the single most commonly skipped item in a pad change.

On an integral caliper, retract the pistons with the correct wind-back tool before refitting, and check that the piston slides back in its bore smoothly. If it does not, the caliper needs servicing rather than refitting.

Refit the caliper and torque the bolts to specification. Wheel bolts also go to specification, and the sequence matters where the manufacturer specifies one. Lower the vehicle, refit the wheel, and do the remaining corners.

If the hydraulic system was opened or fluid was lost, bleed the system until the pedal is firm and there is no air, and check the level afterwards, because bleeding will drop it. Never let air into the system, because a pedal that feels spongy or travels too far is a serious safety issue rather than a nuisance.

Bedding the New Pads

New pads need to transfer an even layer of material onto the disc before they work properly, and this step is what people skip and then blame for the squealing or the long stopping distance that follows. Drive on a quiet road at moderate speed and make a series of firm, controlled decelerations to a walking pace, repeating several times without coming to a complete stop between them. The heat produced transfers the material evenly.

Do not drag the brakes to a stop in one go, and do not do it in heavy traffic, because that is a genuinely dangerous use of the process. Do not bed the pads in at very low speed or while stationary, because that does not generate the heat needed.

Common Mistakes

The list is short and it repeats constantly. Fitting pads onto a disc that needs machining. Reusing the old friction material orientation. Omitting lubricant on the backing plates, which causes squeal. Overtightening the caliper bolts, which is a structural fastener. Forgetting to check the inner pad, which is the one that wears faster on most vehicles. Skipping the bedding, which produces the complaints that get blamed on the pads. And leaving the wheel bolts at a torque that feels right rather than the specified one, which affects handling and safety rather than braking directly.

When to Call a Professional

Call a workshop if the caliper is an integral type and you do not have the correct wind-back tool, if the vehicle uses a retractable parking brake on that axle, if the disc is scored beyond what machining will solve, if you need to bleed the system and have no bleed kit, or if you are at all uncertain about supporting the vehicle safely. The parts are inexpensive and the labour is not, so it is worth asking whether a workshop will supply the pads and fit them, which is usually a much lower rate than having them source both.

Beyond the pad change itself, the habits that keep a set going for a long time are in our guide to extending brake pad life, and it is worth reading before fitting a set rather than after. If this guide was helpful, you may also want to read why a car feels unstable for the mechanical faults that cause the uneven wear which wastes pads, and how to choose a workshop you can trust before booking any brake work.