Volkswagen PASSAT Repair Manual page 243

Assembly overview: brake master cylinder/brake servo
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Page 2 of 4
6 - Brake servo
On gas engines the
vacuum required is
taken from the intake
manifold.
On Diesel engines an
exhauster is installed
to create the required
vacuum.
Functional check
- With engine
switched off,
depress brake pedal
firmly several times
(to exhaust the
vacuum in the unit).
- Now depress brake
pedal with average
foot pressure, hold
and start engine. If
the servo unit is
working properly, the
pedal will be felt to
give slightly under
foot (servo
assistance becomes
effective).
If faulty replace
complete.
Check valve (item 14 )
is in vacuum hose
Functional check
- It must be possible
to blow through in
direction of arrow.
- Blowing against the
arrow the valve must
seat.
47-2
12/7/2004