1. Connect the SSTs to the brake pipes as shown in the figure.

2. Bleed the air from the brake system.
3. Measure the fluid pressure of the master cylinder and the rear brake.

Fluid pressure

Power brake unit inspection
Dual proportioning valve replacement (without abs)Mazda 6 Service Manual: Contact Authorized Mazda Dealer and Have Vehicle Inspected
If any of the following warning lights or the indicator light turns on/flashes,
the system may have a malfunction. Contact an Authorized Mazda Dealer to have your
vehicle inspected.
...
Mazda 6 Service Manual: A/c unit removal/installation
1. Disconnect the negative battery cable.
2. Discharge the refrigerant from the system. (See RECOVERY.) (See CHARGING.)
3. Drain the engine coolant. (See ENGINE COOLANT REPLACEMENT.)
4. Remove the dashboard. (See DASHBOARD REMOVAL/INSTALLATION.)
5. Remove the theft-deterrent control module. (See ...