GM Service Manual Online
For 1990-2009 cars only

From 48-64 km/h (30-40 mph), apply the brakes gently until the vehicle slows nearly to a stop. Accelerate the vehicle back to 48-64 km/h (30-40 mph) and drive long enough for the brakes to cool -- 30-40 seconds. Repeat this process 5 times, each time allowing sufficient time between stops for the brakes to cool.

Complete the break-in procedure by gently slowing the vehicle from 89-32 km/h (55-20 mph) 4 times. Allow 30 -40 seconds between stops for the brakes to cool. This break-in procedure will reduce brake noise and increase brake life and performance.