Brake Booster, Removing And Installing - BMW 5251 Service Manual

Brakes
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Pump brake pedal a few times to reduce vacuum in brake
booster. This makes removal of check valve easier.
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Remove or loosen hose clamp(s) at check valve.
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Disconnect hoses. Remove valve to test or replace.
NOTE-
If valve is pressed into grommet in vacuum booster, pry it out
carefully.
-
Reinstall valve using new hose clamps
NOTE-
Install the valve so that the molded arrow is pointing toward
the intake manifold.
Brake booster, removing and installing
CAUTIO&
All E39 vehicles sold in the USA are equipped with Antiloclc
Braking System (ABS) and either Automatic Stability Control
(ASC) or Dynamic Stability Control (DSC). In order for the
bralchg and stability controls to work properk if brake fluid
lines are disconnected and reconnected, male sure that the
brake system is bled by an authorized BMW dealer or other
qualified repair facility using the BMW Service Tester: See
Brake Bleeding earlier in this group.
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Disconnect negative (-) cable from battery.
I
CAUTION-
I
Prior to disconnecting the battery read the battery discon-
nection cautions given in 001 General Cautions and
I
Warnings.
I
-
Remove bralte master cylinder as described earlier.
-
Disconnect engine vacuum hose from bralte booster.