Rear Buckle Removal/Installation

Switch the ignition off.
Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
Remove the rear seat cushion. (See REAR SEAT CUSHION REMOVAL/INSTALLATION .)
Disconnect the connectors.

Fig 1: Rear Buckle, Connector And Bolts With Torque Specifications
Courtesy of MAZDA MOTORS CORP.
Remove the bolts.
Remove the rear buckle.
Install in the reverse order of removal.