1997 BMW 525i Brake lines

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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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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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340-32
Brakes
The procedure for removing the ABS I ASC or ABS I DSC hy-
draulic unit is similar for all models. The unit is located at the
right rear of the engine compartment.
- Using a clean syringe, empty brake fluid reservoir.
CAUTION-
Brake fluid is highly corrosive and dangerous to the environ-
ment. Dispose of it
properiw
4 Disconnect electrical harness connector (A) at hydraulic unit
(1998 DSC hydraulic unit in V-8 model shown).
Where applicable, detach electrical harness connector to
DSC pressure sensor.
Mark brake lines
(arrows) in relation to their placement on
hydraulic unit. Detach lines from unit using appropriate
sized flare wrench.
Seal open brake fluid lines and bores with suitable plugs to
prevent contamination.
- Carefully push aside brake lines from retainerslgrommets
that may be in the way of hydraulic unit removal. Use care not
to
kink brake lines.
- Remove hydraulic unit mounting screws. Remove hydraulic unit.
- If necessary, separate hydraulic unit from control module.
- Installation is reverse of removal, noting the following:
Check rubber mount for hydraulic unit/control module. Re-
place if damaged.
Make sure all nuts, fluid couplings, thread bores and mat-
ing surfaces are clean.
Avoid bending pins on control module harness connector
when reattaching.
Make sure brake lines are securely seated in grommets
before installing brake lines in hydraulic unit bores.
Bleed brakes using
BMW Service Testeras described earlier.
Tightening torques Brake lines to hydraulic unit
18 Nm (13 ft-lb)
DSC electronic control unit to hydraulic unit 2.9 Nrn (26 in-lb)
(use new screws)
Hydraulic unit to body
8 Nm (6 ft-ib)
Mounting bracket to hydraulic unit 8 Nrn (6 ft-lb)

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INDEX 7
WARNING
Your common sense, good
judgement, and general alertness are
crucial to safe and successful service
work. Before
attempting any work on
your BMW, be sure to read 001
General Warnings and Cautions
and the copyright page at the front of
the manual. Review these warnings
and cautions each time you prepare
to
work on your BMW. Please also
read any warnings and
caulions that
accompany
/he procedures in the
manual.
Jack stands
010-16
Jump starting 010-19
Keys
515-1 1
Knock sensor
see Ignition system
Leak detection,
fuel tanlr
see Fuel tank, leak detection unit
Leather upholstery
see Maintenance, leather
upholstery and trim
LDP
(leak detection pump)
see Fuel
tanir, leal( detection unit
Level sender
see Fuel tank
see also Fuel pump
License
plate iight
630-1 1
Lifters see Cylinder head and vaivetrain
Lifting the car
010-5 Lights
bulb applications
630-2
control module (LCM) 630-3
foglights 630-8 headiighls 630-4
automatic headlight adjustment
(LWR)
630-7
vertical aim system 630-8 interior lights 630-12
bulb applications 630-13
side turn signal 630-9
taillight 630.10 trunk light bulb 630-14
turn signals, taillights 630-12
LOClCS see Central loci(ing
see also Door loclrs
Lubrication system
oil
level warning switch, replacing
119-20
oil pan, removinglinstalling
6-cylinder 119-10
V-E lower 119-13 V-8 upper 119-15
oil pressure
checiring 11
9-4
warning system, testing 119-5 warning switch, replacing 119-20
oil pressure
reliel valve
6-cylinder 119-26
V-8 11 9-27
oil pump, removinglinstalling
6-cylinder
119-22
V-8 1 19-4
troubieshooting 119-3
Luggage compartment
seeTrunk
MAF (mass air flow) sensor
see 130 under appropriate fuel
injection system Maintenance
accelerator linkage
020-14 air filter 020-14
automatic transmission 020-29
battery 020-22
body lubrication 020-31 body and interior 020-31
braire fluid 020-24
brake padlrotor wear 020-24
brake system 020-25 clutch fluid 020-26
cooling system 020-15
CV ioint boots 020-27
differential oil level 020-26
drive bells 020-16 engine comparlmenl 020-14
engine cooling system 020-16
engine oil 020-1 1 exhaust system 020-27
exterior washing 020-31
fluid and lubricant specifications 020-9
fuel lilter 020-27 fuel lanir and fuel lines 20-28
idle speed 020-19
inspection 020-5
interior care 020-31
lealher upholslery and trim 020-31
maintenance tables 020-6
manual transmission oil 020-30
microiilter 020-22 oxygen sensors 130-72, 180-8
parlcing brake 020-25
power steering fluid level 020-20
seat belts
020-32 service indicator 020-3
spark plugs 020-20
special cleaning 020-32 suspension, front 020-29
suspension, rear 020-29
tires 020-29
washing
020-32
waxing 020-32 windshield wiper blade 020-33
wheels, aligning 020-30
Malfunction indicator iight (MIL)
OED-2
Manifold, exhaust
see Exhaust system
Manifold,
intake
see Intake maniiold