1. Remove the clamps and vacuum hose.
2. Apply both suction and pressure to the engine-side hose, and verify that air blows only toward that side.

Air bleeding
Brake pedal inspectionMazda 6 Service Manual: Snow Tires
Use snow tires on all four wheels
Do not go faster than 120 km/h (75 mph) while driving with snow tires. Inflate
snow tires 30 kPa (0.3 kgf/cm2, 4.3 psi) more than recommended on the tire pressure
label (driver's door frame), but never more than the maximum cold-tire pressure
shown on the tir ...
Mazda 6 Service Manual: No.9 noise while operating a/c system
Diagnostic procedure
* : If there is gas leakage, air enters into the A/C system. The desiccant
within the receiver/drier absorbs the moisture from the air and becomes
saturated. If the A/C system is used in this condition, the inside of the A/C
compressor will begin to rust due to this ...