electronic BMW 525i 2001 E39 Repair Manual

Downloaded from www.Manualslib.com manuals search engine
Suspension, Steering and Brakes - General
WHEELS AND TIRES
Tire size is critical to the properoperation of the antilock brake
system and traction control system. Several differentstyles of
wheels in
15,16, and 17 inch diameters are available from an
authorized BMW dealer.
Rim and tire size applications are listed in the table below.
Rim and tire sizes table
ELECTRONIC BRAKE AND STABILITY
CONTROL SYSTEMS
Model
5251
5281
530i
540i (manual
transmission)
540i (automatic
transmission)
All
E39 vehicles are equipped with the Antilock Braking Sys-
tem
(ABS). Early production models featured ABS with Auto-
matic Stability
control (ABSIASC). Later models came
equipped with ABS and Dynamic Stability Control
(ABSIDSC). DSC builds upon the existing ABSIASC system
to provide electronic control of drive and braking systems to
insure vehicle stability.
This manual will refer to these systems as ABS. ASC or DSC
will be specified when necessary. ABS component replace-
ment is covered in
340 Brakes.
Standard
ABS applications are shown in the accompanying table
Rim size
16x7
15x7
16x7
17x8
16x7 Optional
Tire size
225160R-15
235145-1 7
225155-1 6
Rim size
17x8
Front 17
x 8 Rear 17 x 9
17 x 8
Front 17x8
Rear 17x9
Front 17 x 8
Rear 17 x 9 Tire
size
245145R-17
Front 235145-1 7
255140R-17
235145R-17
Front 235145-1 7
Rear
255140R-17
Front 235145-17
Rear 255140R-17

Downloaded from www.Manualslib.com manuals search engine
300-1 2
I Sus~ension, Steerincl and Brakes - General
E39 electronic brake and stability control
systems application table
(528i, 54bi) Traction (ASC) I Hydraulic unit in right rear of engine compartment 1
Identifiers
Year (model)
I No precharge pump 1
Manuf. up to 911998 l~utomatic Stability Control plus I Electronic control module next to glove compartment
System
Precharge pump in
lefl front of engine compartment, below
steering fluid reservoir
Separate rotational rate (yaw) and lateral acceleration sensors
I I
Combined rotational rate (yaw) and lateral acceleration sensors
Electronic control
module next to glove compartment
Hydraulic unit in right rear of engine compartment
Manuf. up to 911999
(540i optional)
I I
ABS system
Dynamic Stability Control (Bosch
DSC
Ill v. 5.3)
The electronically controlled
ABS maintains vehicle stability
and control during emergency braking by preventing wheel
lock-up.
ABS provides optimum deceleration and stability dur-
ing adverse conditions. It automatically adjusts brake system
hydraulic pressure at each wheel to prevent wheel lock-up.
Control
moduleihydraulic unit
in right rear of engine compartment
No precharge pump
Manuf. from
911999
(all models)
Automatic Stability Control (ASC)
Dynamic Stability Control (Boscli
DSC Ill v. 5.7)
NOJE-
ASC (Automatic Stability Control) may also be referred to as
ASCiT (Automatic Stability ControkTraction).
ASC works in conjunction with ABS and the engine manage-
ment system to enhance vehicle control. The main function of
the
ASC system is to maintain the contact between the tires
and the road surface under all driving conditions. This is
achieved through exact application and management of brak-
ing and drivetrain forces.
The
ASC system improves traction by electronically applying
the rear brakes when the rear drive wheels are spinning at a
faster rate than the front wheels. The combined
ABSIASC
control module, operating through the ABS hydraulic control
unit, modulates braking force at the rear wheels.
In addition,
ASC overrides the throttle opening to reduce en-
gine torque and maintain vehicle traction. Because the throt-
tle is controlled electronically, the driver cannot increase
engine power output during
ASC intervention regardless of
how far the accelerator pedal is pushed.

Downloaded from www.Manualslib.com manuals search engine
Front ~us~ensionl
Spread steering knuckle slot in
tool
31 2 200.
pinch collarwith BMW special
4 Worlting in engine compartment at strut tower:
- If applicable, disconnect plug connector at top of strut for
Electronic Damper Control and remove cap from cable.
Remove upper strut bearing mounting fasteners
(arrows).
WARNING-
Do not remove centerstrut retaining nut.
4 Use lever to push down on wheel hub. Tilt strut outward
NOTE-
Use masking tape to protect fender arch from possible dam-
age.

Downloaded from www.Manualslib.com manuals search engine
330 Rear Suspension
General . . . . . . . . . . . . . . . . . . . . . . . . . . . ,330-2
Special tools . . . . . . . . . . . . . . . . . . . . . . . . ,330-2
Rear suspension variations . . . . . . . . . . . . ,330-4
Rear Struts and Springs
(sedan models)
. . . . . . . . . . . . . . . . . . . . ,330-5
Rear strut assembly, removing
and installing
. . . . . . . . . . . . . . . . . . . . . . . ,330-5
Rear strut assembly, disassembling
and assembling
. . . . . . . . . . . . . . . . . . . . . ,330-7
Rear Shock Absorbers and
Springs (Sport Wagon models)
. . . . . ,330-9
Rear shock absorber, removing
and installing
. . . . . . . . . . . . . . . . . . . . . . . ,330-9
Coil spring, removing and installing . . . . . ,330-1 1
Air spring, removing and installing
. . . . . . ,330-12
Rear Suspension Arms,
Subframe and Bushings . . . . . . . . . . ,330-13
Rear suspension arm components . . . . . . ,330-1 3
Swing arm, removing and installing (sedan models)
. . . . . . . . . . . . . . . . . . . . . ,330-1 4
Swing arm, removing and installing (Sport Wagon models)
. . . . . . . . . . . . . . . ,330-16
Swing arm ball joint, replacing . . . . . . . . . ,330-1 9
Upper rear control arm, removing
and installing (sedan models)
. . . . . . . . . . .330-22
Upper rear control arm, removing
and installing (Sport Wagon models)
. . . . .330-23
Upper front control arm (traction strut),
removing and installing
. . . . . . . . . . . . . . . ,330-25
Rear axle assembly, removing and
installing (sedan models)
. . . . . . . . . . . . . ,330-26
Rear axle assembly, removing and
installing (Sport Wagon models)
. . . . . . . ,330-28
Rear subframe mounting bushings,
removing and installing
. . . . . . . . . . . . . . . .330-31
Rear Wheel Bearings . . . . . . . . . . .
Rear wheel bearing carrier, removing
and installing (sedan models)
. . . . . . .
Rear wheel bearing carrier, removing
and installing (Sport Wagon models)
. .
Rear wheel bearing, replacing . . . . . . .
Rear Stabilizer Bar
Stabilizer bar, removing and installing .
Stabilizer bar link, removing
and installing
. . . . . . . . . . . . . . . . . . . .
Electronic Height Control (EHC)
Component Replacement
. . . . . . .
Electronic height control (EHC)
components
.....................
Air compressor pump relay, removing
and installing
. . . . . . . . . . . . . . . . . . . .
EHC control module, removing
and installing
. . . . . . . . . . . . . . . . . . . .
Air supply unit, removing and installing
Ride height sensor, removing
and installing
. . . . . . . . . . . . . . . . . . . .

Downloaded from www.Manualslib.com manuals search engine
--
C. -- -- - -- Rear ~us~ensionl
Depending on year and model applications, the Sport Wagon
rear suspension may be equipped with:
Conventional shock absorbers and coil springs
Electronic height control (EHC) system which incorporates
air springs
NOTE-
. Suspension and EHC troubleshooting is covered in 300
Suspension, Steering and Brakes-General.
EHC system repairs, other than air spring replacement,
are covered in Electronic height control
(EHC) compo-
nent replacement.
Replace shock absorbers and springs in pairs only.
Rear shock absorber, removing and
installing
- Raise car and remove rear wheels,
WARNING-
Male sure that the car is firmly supported on jack stands de-
signed for the purpose. Place jack stands underneath struc-
tural chassis points. Do not place
jack stands under
suspension parts.
CAUTION-
If working on a vehicle with compressedairshock absorbers,
disable air supply pump by disconnecting electrical plug be-
fore performing any repairs. Pump is located beneath a cover
under the spare tire in the floor of the cargo compartment.
- Support swing arm from below
CAUTIOG
The shock absorber prevents the drive axle and wlieel bear-
ing carrier from dropping too far. Supporting the wheel bear-
ing carrier before disconnecting the shock absorber
mounting fasteners prevents damage to the
brake hose,
parking
brake cable and drive axle CVjoints.
- Working in cargo compartment, remove carpet. Remove tri-
angular upper shock mount covers located beside spare tire
well.
- If applicable: Detach air supply line from shock absorber.
Plug ports and lines to keep out dirt.

Downloaded from www.Manualslib.com manuals search engine
Rear Suspension
Air spring, removing and installing
CAUTION-
If vehicle is driven with airspring depressurized, the airspring
will be permanently damaged and must be replaced.
An air spring is made from a flexible rubber material which
forms an airtight cavity. It is pressurized by an air supply
pump activated by an electronic control unit to provide a
vari- . . able spring rate depending on vehicle load
CAUTIOIG
Disable air supply pump by disconnecting electrical plug
before performing any repairs. Pump is located beneath a
cover under the spare tire in the floor of
the cargo compart-
ment.
When removing and installing air connections, extreme
cleanliness must be followed. Small dirt particles can
cause leakage in the system.
Remove luggage compartment floor mat.
- Working above air spring, loosen quick coupling screw con-
nection to allow
air pressure to escape.
- Once pressure has been reduced, retighten screw.
Tightening torque Quick coupling screw
to air pump 2 Nm (18 in-lb)
- Remove quick coupler. Plug openings to keep dirt out,
- Remove air spring mounting clips.
- Raise car and remove rear wheels.
Make sure the car is firmly supported on jack stands de-
signed for the purpose. Place jack stands underneath struc-
tural chassis points. Do not place
jaclc stands under
suspension parts.
- Working underneath rear suspension, lift wheel bearing car-
rier to relieve rear spring tension. Then unbolt air spring
mounting bolt from seat on wheel bearing carrier. Remove air
spring.
NOTE-
Left and right air springs are different. The left air spring is
marked with a red identification
marl. The right air spring is
marked with a blue identification mark.

Downloaded from www.Manualslib.com manuals search engine
---
Rear Suspension
ELECTRONIC HEIGHT CONTROL
(EHC) COMPONENT REPLACEMENT
Sport Premium rear suspension is an option on Sport Wagon
models and standard on
1999 and later V-8 Sport Wagons.
This suspension incorporates electronic height control
(EHC)
using air springs.
With vehicle lifted off the ground,
if the rear air springs can be
compressed by hand, either the spring is defective or the sys-
tem is depressurized.
Locate
EHC faults using BMW scan tools DIS or MoDiC. EHC
description and some troubleshooting is covered in 300 Sus-
pension, Steering and Brakes-General.
Air spring replacement is covered earlier in this chapter. See
Air spring, removing and installing.
CAUTION-
Maintain high levels of cleanliness around air line connec-
tions when disassembling and assembling air suspension
components. Even
small dirt particles can cause leakage in
the pressurized system.
Electronic height control
(EHC) components
1. Air spring
2. 1 liter air reservoir
3. EHC control module
4. Air supply distributor
5. Airsupply pump
(under spare tire)
6. Air spring mounting bolt
(at wheel bearing carrier)
7. Rear ride height sensors
(Hall effect)
8. Air supply pump relay

Downloaded from www.Manualslib.com manuals search engine
General ........................... .34 0.2
Special Tools
....................... .34 0.2
E39 brake system
.................... .34 0.4
Electronic braking and stability control
.... .34 0.4
Troubleshooting
..................... .34 0.5
Warnings and cautions
................ .34 0.7
Bleeding Brakes ................... .34 0.8
Brakes, bleeding
..................... .34 0.9
Brake Pads, Calipers and Rotors ... .34 0.1 1
Braking system components .......... .34 0.11
Brake pads,
checking and replacing ..... .34 0.12
Brake rotors, removing and installing
.... .34 0.15
Master Cylinder .................. .34 0.16
Master cylinder, removing and installing
. .34 0.17
Brake Booster .................... .349 0.1
Brake booster check valve
............ .34 0.19
Brake booster, removing and installing
.. .34 0.20
Parking Brake .................... .34 0.22
Parking brake components
............ .34 0.22
Parking
brake, adjusting .............. .34 0.22
Parking bralte shoes, removing
and installing
....................... .34 0.23
Parking
brake cable, replacing ......... .34 0.24
ABS Component Replacement ..... 340-26
Wheel speed sensor. replacing
......... 340-26
ABS impulse wheel
.................. 340-27
DSC lateral acceleration or
rotational rate (yaw) sensor. replacing
... 340-27
DSC steering angle sensor.
removing and installing
............... 340-28
DSC precharge pump.
removing and installing (1998 models)
... 340-29
DSC pressure sensor
(1 999 - 2002 models) ................ 340-30
ABS /traction electronic control
module
(1 997 -1 998 models) .......... 340-31
ABS
/ DSC control module
(1 999
- 2002 models) ................ 340-31
ABS
/ traction control hydraulic unit.
removing and installing
............... 340-31

Downloaded from www.Manualslib.com manuals search engine
E39 brake system
BMW E39 models are equipped with vacuum power-assisted
four-wheel disc brakes with an integral
Antilock Brake System
(ABS). Single-piston calipers act on vented front and rear ro-
tors. A brake pad wear sensor for each axle indicates when
brake pads need replacement. The dual drum-type parking
brake system is integrated with the rear brake rotors.
Electronic braking and stability control
E39 models were introduced with Automatic Stability Control,
a computer controlled traction control system that uses the
AB5 system in conjunction with engine management controls
to control wheel spin during take-off and maintain vehicle sta-
bility while braking.
Added in the
1998 model year was Dynamic Stability Control
(DSC). This system implements wheel speed modulation
throughout all stages of driving. For example, DSC is able to
reduce understeer by applying differing amounts of braking
force to each wheel, or it can override the engine manage-
ment system during hard cornering.
A summary of distinguishing characteristics of the various
systems is shown in the table
E39 electronic braking and
stability control systems.
For ABS, ASC and DSC system and component descriptions,
see
300 Suspension, Steering and Brakes-General.
WARNING-
A car with electronic stability control is still subject to normal
physical laws. Avoid excessive speeds for the road conditions
encountered.
E39 electronic braking and stability control systems
Year (model)
manuf. up to 911998
(528i, 540i)
manuf. from 911999
(540i optional)*
From
911 999
(ail models) System
Automatic Stability Control (ASC) Identifiers
Electronic control module next to glove compartment
Hydraulic unit in right rear of engine compartment
No precharge pump
Dynamic Stability Control
(Bosch DSC
Ill v. 5.3)
Dynamic
Stabil~ty Control
(Bosch DSC
Ill v. 5.7) Electronic
control module next to glove compartment
Hydraulic unit in right rear of engine compartment
Precharge pump in left front of engine compartment, below steering
fluid reservoir
Separate rotational rate (yaw) and lateral acceleration sensors
Control
modulelhydraulic unit in right rear of engine compartment
No precharge pump
Combined rotational rate (yaw) and lateral acceleration sensors

Downloaded from www.Manualslib.com manuals search engine
Brakes
Warnings and cautions
WARNING-
. E39 cars require special BMWsen/ice equipment toprop-
erly bleed the brake hydraulic system. See Bleeding
Brakes for additional information.
Semi-metallic and metallic brake friction materials in
brake pads or shoes may produce dangerous dust.
Brake fluid is poisonous, corrosive and dangerous to
the environment. Wear safety glasses and rubber
gloves when worliing with
bralie fluid. Do not siphon
brake fluid with your mouth. Dispose of brake fluid
properly
Do not reuse self-locking nuts, bolts or fasteners. They
are designed to be used only once and may fail if re-
used. Always replace them with new self-locliing fas-
teners.
CAUTlOI\C
Immediately clean bralie fluid spilled on painted surfaces
and wash with water, as
bralie fluid will remove paint.
Always use new brake fluid from a fresh, unopened
container.
Brake fluid will absorb moisture from the air.
This can lead to corrosion problems in the
braking sys-
tem, and will also lower the fluid boiling point.
. Plug open lines and brake fluid ports to prevent con-
tamination.
Only tighten brake hoses on front wheels
with wheels
in straight ahead position.
If carrying out electric welding
worlc, be sure to discon-
nect electrical harness connector from electronic con-
trol module.
Do not expose electronic control modules to high sus-
tained heat, such as in a paint drying booth. Maximum
heat exposure:-95°C (203
OF) for short periods of time-
85'C (185°F) for Ions periods of time (approx. 2 hours)