1. Remove the clamps and vacuum hose.
2. Apply both suction and pressure to the engine-side hose, and verify that air blows only toward that side.

Air bleeding
Brake pedal inspectionMazda 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.
...
Mazda 6 Service Manual: Oil cooler
LF, L3
1. Remove the under cover.
2. Drain the engine coolant. (See ENGINE COOLANT REPLACEMENT.)
3. Remove the oil filter cover, and drain the engine oil into a container.
(See OIL FILTER REPLACEMENT.)
4. Remove in the order indicated in the table.
5. Use a clean rag to wipe off the m ...