Legacy Postal Wagon AWD F4-2.2L SOHC (1998)
Vacuum Brake Booster: Description and Operation
DESCRIPTION
The brake booster is a tandem type that utilizes two small diameter diaphragms to provide high brake boosting effects.
OPERATION
1. Brake booster "OFF".
The plunger valve comes in contact with the poppet valve so that atmospheric air passing through the filter and silencer is shut out by the
atmospheric valve (of the poppet valve).
The plunger valve is moved to the key at the right by the return spring so that the poppet valve is held at the right. Since the vacuum valve of the
valve body and the poppet valve are kept away from each other, passage A is linked with passage B and the constant-pressure chamber is also
linked with the variable-pressure chamber. At this point, pressure differential does not occur between the two chambers; the diaphragm plate is
moved back to the right by return spring tension.
