Bedding-In Your Brakes
from Moss Motors and Lorne Goldman

When new pads or brake rotors/discs are installed..or new brake shoes and/or drums, you must carefully and properly bed these new items in to prevent problems. The pads and shoes have a special braking compound on them which must adapt and "marry" to the rotors and drums. Proper bedding in accompishes this. Simply stated, bed-in is the process of depositing an even layer of brake pad material, or transfer layer, on the rubbing surface of the rotor disc or brake drum. Proper bedding in, minimizes the chance of laying down uneven, random patches of the friction material which will be felt as vibration whenever the brakes are applied. Even more importantly, until there is a minimum of braking on the new parts, your braking may not be completely self-adjusted or effective enough for perfect safety.

Most high-performance rotors, pads and shoes come with break-in instructions. The procedures are similar for all. Since you donít come to a complete stop during pad or disc break-in, you have to plan where and when you do this procedure to have the maximum safety during the process. If you come to a complete stop before the break-in process is completed, there is a chance that unequal amounts of brake material will be transferred or pad imprinting will take place, resulting in an irritating vibration during braking.

Properly bedding in a new set of brake pads involves several hard brake applications followed by a cool-off period.

Basic Bed-In Procedure:

1. After installing new disc rotors, and/or brake pads or drums and shoes, perform eight to 10 slowdowns applying moderate pressure from about 30 to 40 mph (50 to 60 kph) without coming to a stop.
2. Make an additional two or three slowdowns applying heavy pressure from about 40 to 45 mph (60 to 70 kph) without coming to a stop.
3. DO NOT DRAG THE BRAKES...a process of actuating the brake pedal and drivbing through the greater resistance.  This heats the material and causes exactly what you are drying to avoid.
4. Allow at least 15 minutes for the brake system to cool down.
5. While the car is at rest during cool-down, DO NOT APPLY THE BRAKES. If you do, material will transfer from the pads to the rotor and probably give you braking vibration.

Imprint of brake pad on rotor

After Brakes Are Bedded-In:

At this point, your new disc rotors and/or pads are ready for normal use with a thin, uniform coating of friction material on the rotors. But the full process of building up the friction layer can take 190 to 300 miles (300 to 500 kms) depending on your driving style. There are two situations you should try to avoid during that time, as they can ruin that fragile friction coating, requiring another round of bedding-in.

First, if you drive gently over a period of time with little heavy braking, you can actually strip off the necessary thin layer of friction material on the surface of the disc. This makes your brakes vulnerable to problems again.

You can restore it by repeating the bedding-in procedure.

Second, if you have an incident where you are driving at high speed and have to brake hard coming to a complete stop with your foot on the brake pedal, the pads will imprint on the disc surface, transferring what seems like a hunk of friction material. This uneven material will cause vibration.

You can generally get rid of the excess material with abrasive friction by repeating the bedding-in process. If itís a bad imprint and you canít get rid of it this way, take your car to a shop with an on-car brake lathe. This process returns the discs to dead flat and then you can re-bed.

So bedding-in may not be a one-time deal, but it will work with patience. If you continue to have trouble, contact the GoMoG Webmaster..