brakes BMW 525i 2001 E39 Repair Manual

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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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Brakes
Parking brake components
1. Clamp
2. Parking brake cable
3. Cable bracket
4. Grommet
5. Adjusting screw
6. Support
7. Shoe expander
8. Return springs
9. Parking brake shoe
10. Lock down spring
11. Shoe retaining pin
12. Adjuster
Parking brake, adjusting
The parking brake is a brake drum system integrated into the I
rear brake rotors. It can be adjusted with the wheels installed,
although the rear wheels will have to be raised off the ground.
- Adjusting the parking bralte becomes necessary under the
following circumstances:
After replacing parking bralte shoes
After replacing rear brake rotors
Excessive stroke of parking brake handle required for ac-
tuation (more then
10 clicks)
After replacement of brake shoe adjuster or parking bralte
cable(s)
- Lift parking brake lever boot out of console. While holding ca-

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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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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.

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340-31
Brakes
ABS 1 traction electronic control module
(1 997 -1 998 models)
4 The traction control electronic control module in 1997- 1998
models is located to the left of the glove compartment.
NOTE-
In both ASC and early DSC systems this location is used for
the electronic control unit.
- Before removing the traction control electronic module, read
any fault codes in memory.
ABS I DSC control module
(1 999 - 2002 models)
The DSC electronic control unit in 1999 and later models
(from 911998) is bolted to the DSC hydraulic unit in the right
rear of the engine compartment.
- Before removing the traction control electronic module, read
any fault codes in memory.
- Install electronic control unit using new screws.
Tightening torque
DSC electronic control unit to 2.9 Nrn (26 in-lb)
hydraulic
unit (use new screws)
- Code newly installed module using either DIS or MoDiC.
- Adjust steering angle sensor using menu item Service func-
tion in
DIS or MoDiC.
ABS I traction control hydraulic unit,
removing and installing
WARNING -
E39 cars require special BMWsewice equipment to properly
bleed the brakes. Removal of the hydraulic unit is not recom-
mended unless this equipment is available. For safety rea-
sons, the
brake system on cars with ABS must be bled using
the procedures described in this repair group.
NOTE-
Before starting this procedure, read control module mem-
ory and print
out diagnostic record.
DSC system: Adjust steering angle sensor using
either
DISplus, GTI, or MoDiC. After completing work, function
test control module.