Impreza Coupe FWD F4-1820cc 1.8L SOHC (1995)
3) Brake booster under medium load
The poppet valve comes in contact with the plunger valve and valve body when a force pushes the center of the reaction disc (at the contact
portion of the plunger valve) via the operating rod and plunger valve. This occurs when brake pedal depression is balanced with a force pushing
the plunger valve (via the push rod and reaction disc) due to the reaction force of oil pressure delivered from the master cylinder.
As a result, pressure differential is maintained between the constant-pressure chamber and variable-pressure chamber unless the pedal depression
force is changed.
4) Brake booster under full-load conditions
When pedal depression increases to such an extent that the variable-pressure chamber is maintained at atmospheric pressure, the maximum
pressure differential acts on the diaphragm plate.
Further pedal depression does not act on the diaphragm plate but rather on the push rod.
