9000 Hatchback L4-2290cc 2.3L DOHC Turbo EFI (1994)
The return passage to the brake fluid reservoir is closed and the pressure in front of the primary piston increases. The pressure also acts on the
secondary piston, pushing it forwards and so closing its return passage also. The hydraulic pressure in the two brake circuits increases and since
the pistons are equally large in area, the pressure in both brake circuits is also equal. The pressure is propagated in the brake system and acts on the
brake piston in each hydraulic body. The brake pistons press the friction pads against the brake discs.
When the brake pedal is released the pistons in the master cylinder return to their resi (brakes off) position and the return passage is opened. The
pressure is relieved and the brake piston in each brake cylinder is returned to the rest (brake off) position by the piston sealing ring.
Brakes Applied (One Circuit Inoperative)
When the brake pedal is depressed and leakage occurs in the primary circuit, for instance, the primary piston is pushed forwards by the pushrod
until it acts mechanically on the secondary piston. The secondary piston closes the return passage and hydraulic pressure builds up in the
secondary circuit only.
If there is a leak in the secondary circuit, the secondary piston will be pushed forwards until it bottoms in the master cylinder.
In both cases, longer pedal travel is required to accomplish the desired braking power.
Brake Fluid Reservior
