ECT BMW 528i 1998 E39 Workshop Manual

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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
The brake booster is mounted to the bulkhead on driver's side
of the engine compartment, directly behind the brake master
cylinder. Intake manifold vacuum acts on a large diaphragm
in the brake booster to reduce brake pedal effort.
Brake booster check valve
The checlc valve in the bralte booster vacuum line prevents
contamination from engine backfires and other sources from
entering the bralte booster.
Location of
check valve varies, depending on year and mod-
el.
4 6-cylinder models (528i):
1. Intake manifold
2 Hose clamp
3. Vacuum line
4. Upper hose bracket
5. Grommet 6. From 911998: Check valve in grommet in booster.
Remove left ventilation filter housing for access.
7. To 911 998: Check valve in vacuum hose. Remove left
ventilation filter housing, peel back trim rubber below
housing and
unclip upper hose brackets to access hose
clamps and valve.
8. Lower hose
bracket
9. Brake master cylinder
10. Brake booster
< 6-cylinder models (525i, 530i): Remove left ventilation filter
housing to access
checlc valve.
1. Vacuum hose
2. Hose clamp
3. Hose bracket
4. Check valve in grommet in booster
5.
Braite master cylinder
6. Grommet
7. Brake booster
4 V-8 models (540i) to 911998: Check valve (arrow) in vacuum
line behind left cylinder head.
- V-8 models (540i) from 911998: Checkvalve in brake booster.
Remove left ventilation filter housing to access valve.

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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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340-25
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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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.

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340-28
Brakes
- Remove sensor mounting screws. Lift sensor away from
bracket.
- Installation is reverse of removal.
CAUTION-
Be sure to tighten the DSC acceleration sensor(s) and
mounting bracket, if applicable, to specified torques. The
sensor
is vibration sensitive and subject to cause DSC
malfunctions if installed improperly.
a After replacing the sensor, perform sensor adjustment
using either DIS or
MoDiC under Service Functions
menu.
Tightening
torques
Lateral acceleration I rotational rate sensor 8 Nm (6 R-ib)
to bracket
Sensor bracket to body
8 Nm (6 ft-lb)
DSC steering angle sensor, removing and
installing
4 Remove lower dash panel mounting fasteners (A) and (5).
- Remove steering column lower trim panel. See 320 Steering
and Wheel Alignment.
Remove steering shaft clamping bolt (arrow).
Disconnect sensor wiring harness connector.

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Remove snap ring from steering shaft.
- Slide steering angle sensor off steering shaft
< Installation is reverse of removal, noting the following.
Take care to line up loclting pin
(arrow) with mount hole in
sensor.
Perform steering angle offset test using BMW scan tools
DISplus, GT1, or MoDiC. Once calibrated, the sensor
sends a confirmation ID code to the DSC control module
to indicate proper calibration.
DSC precharge pump, removing and
installing
(1 998 models)
1998 V-8 cars with Bosch DSC Ill v. 5.3 are equipped with a
DSC precharge pump mounted in the engine compartment.
There is no separate precharge pump in the Bosch DSC
Ill v.
5.7 system (1999 models and later).
WARNING-
E39 cars require special BMWservice equipment to properly
bleed the brakes. Removal of hydraulic components is not
recommended unless this equipment is available. For safety
reasons, the
brake system on cars with ABS must be bled us-
ing the procedures described in this repair group.
- Using a clean syringe, empty brake fluid reservoir.
CAUTIOI\C
Brake fluid is highly corrosive and dangerous to the environ-
ment. Disoose of it
orooerlv.
Working at precharge pump, disconnect hydraulic lines (A)
and electrical harness connector (6). Clean up dripping fluid.
hydraulic unit. Label all
con-

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1 Brakes
- Remove precharge pump mounting bracket fasteners and re-
move pump.
- Installation is reverse of removal, noting the following:
Be sure to replace rubber pump mounts if damaged
01
worn.
Bleed brakes as described earlier.
Tightening torque Brake line
to precharge pump 18 Nrn (13 ft-lb)
DSC pressure sensor (1 999 - 2002 models)
On 1999 and later DSC systems, the DSC pressure sensor is
screwed into the DSC hydraulic unit (right rear of engine com-
partment).
WARNING-
* €39 cars require special BMW service equipment to prop-
erly bleed the brakes. Removal of the
DSCpressure sensor
is not recommended unless this equipment is available. For
safety reasons, the brake system on cars with ABS must be
bled using the procedures described in this repair group.
Switch off ignition and remove
key to male sure brake
system cannot be activated.
- Disconnect electrical harness connector at switch.
- Use BMW special tool 34 5 160 to remove and install sensor.
Inspect threads and sealing surfaces for damage.
* Work quicltly to avoid excessive brake fluid leakage.
Tightening torque
Pressure sensor
to hydraulic 19 Nrn (14ft-lb)
unit
- Reconnect harness connector
- Bleed front brakes as described earlier.
- Press on brakes and check for leaks at sensor.
- Turn on ignition and firmly depress brake pedal. Check that
DSC warning light does not come on.