engine AUDI A4 1998 B5 / 1.G Master Cylinder 23mm Workshop Manual

47-31


7 -
Brake servo
On gasoline engines vacuum is supplied
from the intake manifold On Diesel engines vacuum is supplied from
the vacuum pump
Functional check:
- With engine switched off, depress brake
pedal firmly several times (to deplete
vacuum in brake servo).
- Depress and hold brake pedal with
average foot pressure and start engine. If
servo is working properly, pedal will be
felt to give slightly under foot (servo
assistance becomes effective).
If malfunctioning:
- Replace as complete unit only.Check valve in vacuum hose - 9 -Removing and installing page 47
-37
Adjusting ball head Fig. 1
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ylinder with 23.81 mm
(0.937 in.
) piston diameter and brake servo, com
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47-34

Brake master cylinder with 23.81 mm
(0.937 in.) diameter piston, removing
and installing


Special tools and equipment
Sealing plugs from repair kit, Part No. 1H0 698
311A

CAUTION!

Part numbers are listed here for reference
only. Always check with your Parts
department for the latest information.

Removing

- Attach bleeder hose and bleeder bottle to left-
front brake caliper bleeder screw and open
bleeder screw.

- Operate brake pedal to pump out as much brake
fluid as possible.

- Close left-front bleeder screw.

- Cover engine compartment to catch any spilled
brake fluid.

CAUTION!
Pa
ge 6 of 15 Brake master c
ylinder with 23.81 mm
(0.937 in.
) piston diameter and brake servo, com
ponent summar
y
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p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.SU03.47.6

47-38

- Cover engine compartment to catch any spilled
brake fluid.

CAUTION!

Brake fluid must not be allowed to come into
contact with paintwork because of its caustic
effect.

- On vehicles with manual transmissions, disconnect clutch master
cylinder supply hose -1- and seal with plug.
- Disconnect harness connector from brake fluid level warning switch -2-.

- Disconnect brake lines -1- on brake master cylinder and seal brake
lines and threaded holes using plugs from repair kit.
-
Remove T45 Torx bolts -2- from brake servo.- Disconnect vacuum hose from brake servo.
Pa
ge 13 of 15 Brake master c
ylinder with 23.81 mm
(0.937 in.
) piston diameter and brake servo, com
ponent summar
y
11/20/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.SU03.47.6