Legacy Outback Limited AWD F4-2.5L DOHC (1998)
1. Failure of primary circuit.
If the primary circuit fails, the fail-safe piston and balance piston are moved rightward by the fluid pressure in the master cylinder in the secondary
circuit until the piston contacts the plug. In this case, the balance piston remains off the seal (2), and no split point is created in the graph. That is,
the fluid pressure in the secondary side rear wheel cylinder is equal to the fluid pressure in the master cylinder.
2. Failure of secondary circuit.
If the secondary circuit fails, the balance piston is moved leftward by the fluid pressure in chamber B until the end of the piston contacts the
stopper. Since sectional area A1 is greater than A2, the piston remains unmoved even after the master cylinder fluid pressure has reached the split
point, and the piston is kept off the seal (1). Hence, no split point is created in the graph, and the rear wheel cylinder fluid pressure of the primary
circuit is kept equal to the master cylinder fluid pressure.
