1. Inspect the tire inflation, and adjust to the recommended pressure as necessary.
2. Inspect the front wheel bearing play and correct it if necessary. (See Wheel Bearing Play Inspection.)
3. Inspect the wheel and tire runouts. (See SUSPENSION.)
4. Inspect the ball joints and steering linkage for excessive looseness.
5. Shake the vehicle to inspect the operation of the shock absorbers.
Note
6. Measure the height from the center of the wheel to the fender brim. The difference between the left and right measurement must not exceed 10 mm {0.39 in}.

Wheel alignment
Front wheel alignmentMazda 6 Service Manual: No. 1 one or more on-board diagnostic functions inoperative
When performing an asterisked (*) troubleshooting inspection, shake the
wiring harness and connectors while doing the inspection to discover whether
poor contact points are the cause of any intermittent malfunctions. If there
is a problem, check to make sure connectors, terminals and wir ...
Mazda 6 Service Manual: Dual proportioning valve replacement (without abs)
1. Remove in the order indicated in the table.
2. Install in the reverse order of removal.
Dual Proportioning Valve Installation Note
Install the dual proportioning valve so that the R mark faces the left side
of the vehicle.
...