Brake Pedal Reserve Distance: A; Brake Servo System - Subaru IMPREZA 2004 Service Manual

3) Check the pedal stroke.
While the engine is idling, depress the brake pedal
with a 490 N (50 kgf, 110 lb) load and measure the
distance between brake pedal and steering wheel.
With the brake pedal released, measure the dis-
tance between pedal and steering wheel again.
The difference between the two measurements
must be less than specified value. If the distance is
more than specified, there is possibility of air inside
the hydraulic unit.

Brake pedal reserve distance: A

90 mm (3.54 in)/ 490 N (50 kgf, 110 lb) or less
= A
1 2
(B)
(A) Steering wheel
(B) Toe board
4) Check to see if air is in the hydraulic brake line
by the feel of pedal operation. If air appears to exist
in the line, bleed it from the system.
5) Check for even operation of all brakes, using a
brake tester or by driving the vehicle for a short dis-
tance on a straight road.

2. BRAKE SERVO SYSTEM

1) With the engine off, depress the brake pedal
several times applying the same pedal force: Make
sure the travel distance should not change.
2) With the brake pedal depressed, start the en-
gine: Make sure the pedal should move slightly to-
ward the floor.
3) With the brake pedal depressed, stop the engine
and keep the pedal depressed for 30 seconds:
Make sure the pedal height should not change.
4) Check valve is built into the vacuum hose. Dis-
connect the vacuum hose to inspect function of
check valve.
Blow air into the vacuum hose from its brake boost-
er side end: Air must flow out of engine side end of
hose. Next blow air into the hose from engine side:
Air should not flow out of hose.
Brake Line
(A)
1
2
PM-00045
PM-33
PERIODIC MAINTENANCE SERVICES
Replace both check valve and vacuum hose if the
check valve is faulty. Engine side of vacuum hose
is indicated by marking "ENG" as shown.
(A)
(A) Engine side
(B) Brake booster side
(C) ENG
5) Check the vacuum hose for cracks or other dam-
age.
NOTE:
When installing the vacuum hose on the engine
and brake booster, do not use soapy water or lubri-
cating oil on their connections.
6) Check vacuum hose to make sure it is tight and
secure.
(B)
(C)
PM-00046