1. Remove the drive belt. (See DRIVE BELT REPLACEMENT.)
2. Verify that the drive belt auto tensioner moves smoothly in the operational direction.

3. Turn the drive belt auto tensioner pulley by hand and verify that it rotates smoothly.
4. Install the drive belt. (See DRIVE BELT REPLACEMENT.)
Drive belt replacement
Valve clearanceMazda 6 Service Manual: Rear seat disassembly/assembly
4SD
1. Disassemble in the order indicated in the table.
2. Assemble in the reverse order of disassembly.
5HB
1. Disassemble in the order indicated in the table.
2. Assemble in the reverse order of disassembly.
...
Mazda 6 Service Manual: Rear door unit removal/installation
1. Remove the rear door glass.
2. Remove the inner handle.
3. Remove the rear door speaker.
4. Disconnect the power window motor connector, and power door lock actuator
connector.
5. Remove the rear door harness from the rear door unit.
6. Remove the bolts.
7. Remove the rear door lock act ...