Mazda CX-9 Grand Touring 2009 Manual page 532

2008 Mazda CX-9 Grand Touring
2008 BRAKES Conventional Brake System - Mazda CX-9
The following are the main possible causes of brake judder:
Due to an excessive runout (side-to-side wobble) of disc plate, the thickness of disc plate is uneven.
If the runout is more than 0.05 mm {0.002 in} at the position 10 mm {0.39 in} from the disc plate edge,
uneven wear occurs on the disc plate because of uneven pad/plate contact.
If the runout is less than 0.05 mm {0.002 in}, uneven wear does not occur.
The disc plate is deformed by heat.
Repeated panic braking may raise the temperature in some portions of disc plate by approx. 1,000 °C {1,832 °
F}.
This results in deformed disc plate.
Due to corrosion, the thickness and friction coefficient of disc plate change.
If a vehicle is parked under damp conditions for a long time, corrosion occurs on the friction surface of disc
plate.
The thickness of corrosion is uneven and sometimes appears like a wave pattern, which changes the friction
coefficient and causes a reaction force.
Inspection and repair procedure