Subaru 2002 Impreza Service Manual page 337

P R 0 PO RTlO N I N G VALVE
Brakes
A: OPERATION
1)
Operation before the split point
The piston is held pressed toward the left by the spring so that the piston is kept away from its lip
seal.
Under this condition, fluid pressure
"P3"
to the rear wheel cylinders is equal to fluid pressure
"P2"
from the master cylinder.
I
-4
(1)
To rear wheel cylinder
(2) From master cylinder
(3) Lip seal
NF0250
(4) Spring
( 5 ) Piston
BR-11