1. Remove the rear seat cushion.
2. Remove the bolts.

3. Remove the rear buckles.
4. Install in the reverse order of removal.
Front buckle removal/installation
Seat belt inspectionMazda 6 Service Manual: General procedures
PRECAUTION (SUSPENSION)
Wheels and Tires Removal/Installation
When a wheel is installed, tighten it to 88-118 N·m {9.0-12.0 kgf·m,
65.0-87.0 ft·lbf}.
Suspension Links Removal/Installation
Tighten any part of the suspension that uses rubber bushings only after the
vehicle has been lowered ...
Mazda 6 Service Manual: Radiator cap
Warning
Never remove the radiator cap while the engine is running, or when
the engine and radiator are hot. Scalding coolant and steam may shoot out
and cause serious injury. It may also damage the engine and cooling system.
Turn off the engine and wait until it is cool. Even then, be ve ...