Bedding In New Brake Pads: The First 200 Miles Matter

New pads need a controlled break-in to transfer material to the rotor evenly. Skip it and you get noise, pulsation and weak braking. How to do it right.

New brake pads do not work at full strength the moment they are fitted. They need a short break-in period, called bedding, during which a thin, even layer of pad material transfers onto the rotor face. Get that layer down evenly and the brakes are quiet, smooth and strong for their whole life. Get it down unevenly and you have pulsation and noise within a few weeks.

What bedding does

A brake works by friction between the pad and a transfer layer of pad material on the rotor, not between the pad and bare iron. Bedding builds that layer. It also cures the resins in a fresh pad by bringing it through a controlled heat cycle, and it mates the pad surface to the exact profile of the rotor.

What happens when it is skipped

• Uneven deposits. Braking hard on fresh pads then sitting at a light with the pedal held down leaves a thick patch of material on one spot of the rotor. That patch is the pulsation people call a warped rotor.
• Glazing. Overheating a pad before the resins are cured hardens the surface into a shiny, low-friction layer. Glazed pads feel weak and squeal.
• Noise. A pad that has not bedded chatters against a rotor it has not mated to.
• Reduced stopping power until the layer eventually forms on its own, which can take hundreds of miles of gentle use.

The procedure

Find a stretch of road with no traffic where you can accelerate and brake repeatedly without holding anyone up. The frontage roads along Loop 289 early in the morning, or a quiet farm-to-market road, work. Then:

1. 1Drive gently for the first few miles to warm the brakes and confirm everything feels normal.
2. 2From around 35 mph, brake firmly, but not to a full stop, down to around 10 mph. Do not lock the wheels or trigger ABS.
3. 3Accelerate back up and repeat. Do this six to ten times with a short gap between each to let the brakes cool slightly.
4. 4Follow with a few miles of driving with minimal braking so the brakes cool fully.
5. 5Do not come to a complete stop and sit with the pedal pressed while the brakes are hot. If you must stop, use the parking brake or shift to park and take your foot off the pedal.

For the next couple of hundred miles

Avoid towing heavy or making long hard descents until the pads have some miles on them. Brake progressively rather than stabbing at the pedal. Light noise in the first few days is normal and should fade. Noise that gets worse or a pulsation that appears is not, and is worth a call. Why brakes are noisy after a brake job covers what is normal and what is not.

New pads on old rotors

Bedding assumes the rotor surface is clean. New pads on a rotor with old transfer layer, scoring or a lip at the edge will bed to that surface and take on its faults. When we fit new pads without new rotors, the rotor is machined or at least cleaned so the pad has a proper surface to mate to. That is part of what separates a proper brake service from a pad slap.

Frequently asked questions

Does the shop bed the pads before I pick up the vehicle?

We do the initial heat cycles on the test drive where the job warrants it, and we tell you what to do and avoid for the first couple of hundred miles. The full process takes real miles that happen on your drive home.

Do ceramic pads need bedding?

Yes. Every pad material needs a transfer layer. Ceramic pads are more forgiving of a skipped bed-in but still benefit from one.

What if the pads smell during bedding?

A hot, slightly acrid smell during the firm stops is normal. Smoke, or a smell that continues after the brakes have cooled, is not.

Questions about a fresh brake job, or one that never felt right? Call (806) 458-2709 or come by 13209 Frankford Ave, Suite 29, Lubbock. Drivers make the trip in from Shallowater and across the South Plains for it.