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.- -
Brakes
Disconnect master cylinder brake lines (A)
Plug open brake lines to prevent contamination.
Remove master cylinder mounting nuts
(6) and remove
cylinder.
NOTE-
It may be necessary to remove the brake booster with master
cylinder attached due to limited access.
Bralce master cylin-
dercan then be removed from booster. See Brake booster,
removing and installing later
in this repair group.
- During reinstallation, make sure all nuts, fluid couplings,
thread bores, and mating surfaces are clean.
- Mount master cylinder to bralte booster using new sealing O-
ring and new self-locking nuts.
CAUTIOI\C
* Be sure to align master cylinderpushrod and booster
pushrod.
* Do not over-torque master cylinder mounting nuts. This
could damage the brake booster and prevent proper
vacuum build-up.
Tightening torque Brake master cylinder to brake booster
26 Nm (19 ft-lb)
- Connect bralte fluid lines to master cylinder.
Tightening torque Brake fluid line to master cylinder
18 Nm (13 ft-lb)
- Carefully reinstall fluid reservoir using new sealing grommets.
- Reconnect precharge pump fluid supply hose, if applicable. -
- Reconnect hydraulic clutch fluid supply hose, if applicable.
- Remainder of installation is reverse of removal.
Top up with fresh brake fluid.
Bleed entire brake system as described earlier
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Brakes
- Pump brake pedal a few times to reduce vacuum in brake
booster. This makes removal of
check valve easier.
- Remove or loosen hose clamp(s) at check valve.
- 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.
- 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.
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1 Brakes
Pull down panel
If applicable, disconnect electrical harness
rows) from 16-pin OBD-ll plug.
Remove panel from interior. connectors
(ar-
Working
above and in front of pedals, remove locking clip (A)
and slide brake booster pushrod off bralte pedal pin. Remove
brake booster mounting nuts
(6).
Working in engine compartment, carefully separate bralte
booster from engine compartment bulkhead.
CAUTION-
Do not use force on booster when separating from bulkhead.
This can damage booster and pushrod.
Remove booster by tilting out in direction of engine. Lift
booster up and out of engine compartment.
- Installation is reverse of removal, noting the following:
Make sure all nuts, fluid couplings, thread bores and mat-
ing surfaces are clean.
Replace bralte booster self-locking mounting nuts.
Replace sealing O-ring between master cylinder and bralte
booster.
Bleed bralte system as described earlier.
CAUTION--
Do not over-torque tlie master cylinder mounting bolts.
This could damage the
bralce booster and prevent proper
vacuum build-up.
After
30 minutes of use recheclc the torque on bralce
booster mounting nuts.
Tightening torques
Brake master cylinder to brake booster
26 Nm (19 it-lb)
Brake booster to bulkhead 22 Nm (16 it-lb)
(Recheck torque after
30 minutes of use.)
Brake fluid line to master cylinder 18 Nm (13 it-lb)
NOTE-
When replacing the brake booster check valve or vacuum
hose, install the valve so that the molded arrow is pointing to-
ward the
fntalce manifold. Use new hose clamps
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340-23
Brakes
- Using flat-bladed screwdriver, reach into brake drum through
lug bolt hole. Turn brake adjuster until wheel no longer turns.
Back adjuster off
12 notches.
Parking brake adjusting (initial)
Back
off adjuster through wheel
lug bolt hole 12 notches
- Working inside car, set parking brake several times to seat
cable. Then pull parking brake
lever up two notches. Tighten
cable adjusting nuts until it is just possible to turn rear wheels
with slight resistance.
- Release lever and make sure rear wheels turn freely
- Turn on ignition. Pull up parlting brake lever 1 notch and
make sure that parking bralte warning light comes on. if not,
adjust parking bralte warning light contact switch.
- Install parking brake lever boot. Install road wheel lug bolts.
Tightening torque Road
wheel to hub 120 i. 10 Nrn (89 i- 7 ft-lb)
Parking brake shoes, removing and
installing
- Raise rear of car and remove road wheels.
WARNING-
Make sure that the car is firmly supported on jack stands de-
signed for
the purpose. Place jack stands beneath structural
chassis points. Do not place
jaclc stands under suspension
parts.
- Without disconnecting brake fluid hose, remove rear bralte
calipers from trailing arms. Remove rear brake rotors as de-
scribed earlier.
CAUTION-
Do not let the brake caliper assembly hang from the brake
hose. Support caliper from chassis with strong wire.
4 Unhook return sprlngs (arrows) from brake shoes
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340-24
Brakes
4 Remove brake shoe retaining pins using BMW special tool
34 4 000 or equivalent.
Rotate retainer
114 turn to release.
Spread shoes apart and lift out.
4 Note position of bralte shoe adjuster (arrow).
Right side is illustrated. Left is mirror image of this.
- Apply thin coat of grease to sliding parts and pins before re-
assembly.
- Installation is reverse of removal. Be sure to adjust parlting
bralte cables as described earlier.
Tightening torque
Road wheel to
hub 120 i lo Nm (89 i 7 ft-lb)
Parking brake cable, replacing
The parking brake is actuated by two separate Bowden ca-
bles. Each cable can be replaced separately.
- Working inside car, gain access to base of parking brake -
handle by removing center console storage tray and center
armrest, as necessary.
4 Use BMW special tool 34 1 030 or equivalent deep 10 mm
socket to remove parlting brake cable
loclc nuts (A) at base of
parking brake handle.
- Raise rear of car.
WARNING -
Male sure that the car is firmly supported on jack stands de-
signed for the purpose. Place jack stands beneath structural
chassis points. Do not place jaclc stands under suspension
Darfs.
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340-25
Brakes
- Remove complete exhaust system as described in 180 Ex-
haust System.
- Remove center tunnel heat shield.
< Pull parlting brake cable out of body guide tube (arrow) and
detach from routing bracltets, noting correct routing for rein-
stallation.
- Remove parlting bralte shoes as described earlier.
4 Pull shoe expander (A) forward, disconnect parlting bralte
cable
(B) and remove expander.
4 Reroute new cable under car, attaching to bracltets (arrows).
- Remainder of installation is reverse of removal.
Adjust parking brake as described earlier.
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1 Brakes
ABS COMPONENT REPLACEMENT
CA UTIOW-
If the tires on the car are of different makes, the ABS/trac-
tion controlsystem may overreact. Only fit tires of the same
make and treadpattern.
In adverse conditions, such as trying to rock the car out
of deep snow or other soft surface, or when snow
chains are fitted, it is advisable to switch off traction
control and allow
tlie car driveline to operate conven-
tionally.
All E39 vehicles are equipped with
Antilock Braking System
(ABS). Early production models featured ABS with Automatic
Stability Control (ABS
I ASC). Later models came equipped
with ABS and Dynamic Stability Control (ABS
/ DSC). This
manual will refer to these systems as ABS. ASC or DSC will
be specified when necessary.
For ABS system and component descriptions, see
300 Sus-
pension, Steering and Brakes-General.
Wheel speed sensor, replacing
- Raise applicable end of car.
Make sure that the car is firmly supported on
jack stands de-
signed for the purpose. Place
jack stands beneath structural
chassis points. Do not place jack stands under suspension
< Front sensor: Unscrew mounting bolts (arrows) at steering
knuckle.
4 Rear sensor: Unscrew mounting bolt (arrows) in rear wheel
bearing carrier.
NOTE-
ABS wheelspeed sensor application may vary depending on
traction control system installed.
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4 Disconnect and remove speed sensor electrical harness (ar-
row) from retaining mounts. (Lefl front wheel shown).
- During installation, apply thin coat of StaburagsBNBU 12/K
or equivalent grease to speed sensor and housing.
- Installation is reverse of removal.
Tightening torque
ABS wheel speed sensor to steering knuckle or 8 Nm (6 It-lb)
rear wheel bearing carrier
ABS impulse wheel
The front and rear impulse wheels are integral with the inner
wheel bearing seal and not available as separate part. See
310 Front Suspension or 330 Rear Suspension for wheel
bearing replacement procedures.
DSC lateral acceleration or rotational rate
(yaw) sensor, replacing
DSC system on 1998 cars (Bosch DSC Ill v. 5.3): Lateral ac-
celeration sensor and rotational rate (yaw) sensor are sepa-
rate units, both mounted underneath or in front of driver's
seat.
DSC system on 1999 and later cars (Bosch DSC
Ill v. 5.7):
Lateral acceleration sensor and rotational rate (yaw) sensor
are combined into one unit, located under driver's seat.
- Remove driver's seat. See 520 Seats.
- Lateral acceleration sensor (1 998 models): Remove lower
lefl door pillar trim (driver's
kick panel) to access sensor. Pull
up carpet as necessary to reach sensor harness connector
or fasteners.
4 Rotational rate (yaw) sensor (1998 models): Remove plastic
trim at door sill to access sensor (arrow). Pull up carpet and
move insulation forward as necessary to reach sensor har-
ness connector or fasteners.
- Combined lateral acceleration / rotational rate (yaw) sensor
(1 999 and later models): Remove plastic trim at door sill to
access sensor. Pull up carpet and move insulation forward as
necessary to reach sensor harness connector or fasteners.
- Disconnect electrical harness connector at sensor.
- Combined sensor (1 999 and later models): Remove sensor
bracket mounting screws.