All vehicles are subject to condition a) whilst only some vehicles are subject to condition b)

a) Improper sealing of parking brake caliper may allow water entry, causing rust on the parking brake shaft. As a result the brake shaft may stick, and this may allow the vehicle to roll away when parked;

b) A defect with the parking brake automatic adjuster may fail to compensate for brake pad wear, and this may allow the vehicle to roll away when parked.