1999 BMW 540i steering wheel

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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.

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Suspension, Steering and Brakes - ~enerail
The main components of the system are the wheel speed
(pulse) sensors, the
ABSIASC or ABSIDSC control module,
and the hydraulic control unit.
Traction control also comes into operation during decelera-
tion. Decelerating on snowy or icy road surfaces can lead to
rear wheel slip. If a rear wheel starts to drag or lock up, the
ASC system can limit the problem by adjusting throttle, fuel
injection and ignition timing.
4 A switch (arrow) on the center console is used to toggle the
ASC on or off.
NOJE-
Even with the ASC system turned off, if the ASC control mod-
ule senses a difference in wheel speed (one wheel spinning)
the
ASC system applies modulated braling force to the slip-
ping wheel until traction is regained. There is no override of
fuelinjection function.
The ASC system is designed to be maintenance free. There
are no adjustments that can be made. Repair and trouble-
shooting of the ASC system requires special test equipment
and knowledge and should be performed only by an autho-
rized
BMW dealer.
ABSIASC traction
I 1.
control system
Wheel speed sensor
Wheel speed pulse wheel
Brake disk
Brake caliper
ABSIASC hydraulic unit
Brake master cylinder
Pedal operated throttle valve
ASC controlled throttle valve
Engine control module (ECM)
Accelerator pedal
ABSlASC control module

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Suspension, Steering and Brakes - General
Front ride height specifications
(measurement
A)
E39 6-cylinder (5251,5281,530i) models
E39
V8 (540i) models
Wheel size
15 inch
16 inch
17 inch
18 inch
Maximum variation between sides: 10 mm (0.4 in)
Maximum deviation from specifications: 10 mm (0.4 in)
Standard
suspension
579 mm (22.8 in)
592 mm (23.3 in)
607 mm (23.9 in)
620 mm (24.4 in)
Wheel size
15 inch
16 inch
17 inch
18 inch Sports suspension
559
mm (22.0 in)
572 mm (22.5 in)
587 mm (23.1 in)
600 mm (23.6 in)
Maximum variation between sides: 10 mm (0.4 in)
Maximum deviation from specifications: 10 mm (0.4 in)
Standard
suspension
579 mm (22.8 in)
592
mm (23.3 in)
607 mm (23.9 in)
620 mm (24.4 in) Rough
road suspension
599
mm (23.6 in)
612 mm (24.1 in)
627 mm (24.7 in)
640 mm (25.2 in)
Sports suspension
559 mm (22.0 in)
572 mm (22.5 in)
587 mm (23.1 in)
600
mm (23.6 in)
M sports package
559 mm (22.0 in)
572 mm (22.5 in)
587 mm (23.1 in)
600 mm (23.6 in)
Rough road suspension 599 mm (23.6 in)
612
mm (24.1 in)
627
mm (24.7 in)
640
mm (25.2 in)
M sports package
562 mm (22.1 in)
575 mm (22.6 in)
590
mm (23.2 in)
603
mm (23.7 in)

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300-1 6
I Suspension, Steering and Brakes - General
Rear
ride height specifications
(measurement
A)
E39 6-cylinder (5251,5281,530i) models
E39 VB (540i) models
Wheel size
15 inch
16 inch
17 inch
18 inch
Maximum variation between sides: 10
mm (.04 in)
Maximum deviation from specifications: 10
mm (.04 in)
Standard
suspension
547 mm (21.5 in)
560
mm (22.0 in)
575 mm (22.6 in)
588 mm (23.1 in)
I I I I I
Maximum variation between sides: 10 mm (.04 in)
Wheel
size
15 inch
16 inch
575 mm (22.6 in)
Maximum deviation from specifications: 10 mm
(.04 in)
Sports suspension
532 mm (20.9 in)
545 mm (21.5 in)
560 mm (22.0 in)
573
mm (22.6 in)
Rough road
suspension
567
mm (22.3 in)
580 mm
( in)
E39 Sport Wagon models
M sports package
536
mm (21.1 in)
549 mm (21.6 in)
Standard
suspension
547 mm (21.5 in)
560 mm (22.0 in)
588 mm (23.1
in)l 573 mm (22.6 in)/ 603 mm (23.7 in)l 608 mm (23.9 in)l 577 mm (22.7 in)
560
mm (22.0
in) Ride level
control
562
mm (22.1 in)
575 mm (22.6 in)
590 mm (23.2 in)
603 mm (23.7 in)
Sports suspension 532
mm (20.9 in)
545 mm (21.5 in)
590
mm (23.2 in) Rough
road
suspension
567
mm (22.3 in)
580 mm (22.8 in)
595 mm (23.4 in)
608 mm (23.9 in)
Ride level control
562
mm (22.1 in)
575 mm (22.6 in)
Wheel size
15 inch
M sports package
532
mm (20.9 in)
545
mm (21.5 in)
560 mm (22.0 in)
573 mm (22.6 in)
595
mm (23.4 in)
Sports suspension with
air spring
548 mm (21.5 in)
Standard
suspension
548
mm (21.5 in)
16 inch
17 inch
18 inch 564
mm (22.2
in)
Maximum variation between sides: 10 mm
(.04 in)
Maximum deviation from specifications: 10 mm
(.04 in) 561
mm (22.0 in)
576
mm (22.6 in)
589
mrn (23.1 in)
561
mm (22.0 in)
576 mm (22.6 in)
589 mm (23.1 in) Ride level
control
563
mm (22.1 in) Rough road suspension
568 mm (22.4 in)
576 mm (21.6 in)
591 mm (23.2 in)
604 mm (23.7 in) 581
mm (22.9
in)
596
mm (23.5 in)
609 mm (24.0 in)

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31 0-5
Front ~uspensionl
Front strut assembly, removing and
installing
- Raise car and remove front wheel.
WARNING-
Make 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.
- Unbolt bralte caliper assembly, lkeeping bralte hose connect-
ed. Secure brake caliper to body with wire. Do not let it hang
from brake hose. See
340 Brakes.
Remove ABS pulse sensor mounting bolts (arrows) and re-
move sensor from housing.
Detach ABS sensor wire harness and bralte pad wear sensor
wire harness (if equipped) from strut housing.
Loosen and remove stabilizer bar link mounting nut while
counterholding
link ball joint. Disconnect stabilizer link from
strut.
NOTE-
Use a thin wrench to counterhold shaft of stabilizer bar link
ball joint.
- Cars equipped with vertical headlight adjustment system:
Disconnect control arm from level sensor.
4 Remove outer tie rod end nut. Use BMW special tool 31 2
240 or equivalent to press tie rod end out of steering arm.

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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.

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31 0-8
Front Suspension
Slide strut assembly out of steering lknucltle pinch collar. If
necessary use pry bar.
CA UTIOI\C
Do notpullstrut out of steering knuckle with twisting motion.
This can scratch and damage the strut.
Disassemble and reassemble strut assembly as described
later.
When installing new strut, be sure to align locator letter (A)
on strut body with slot in steering
lknuckle pinch collar (6).
Struts are marked with L for left and R for right.
Remainder of installation is reverse of removal.
Make sure strut shoulder (below locator letter) bottoms out
in steering knuckle pinch collar.
Use new self-locking nuts and bolts.
When attaching stabilizer
lrnk to strut, use a thin wrench to
counterhold
link ball joint while t~ghtening nut.
- Have car professionally al~gned when job IS complete.
Tightening torques
Brake caliper to steering knuckle
110 Nm (81 ft-ib)
Road wheel to hub 120 ti0 Nm (89 t7 ft-lb)
Stabilizer bar
link to strut 65 Nm (48 It-lb)
Steering knucltle pinch bolt at strut 81 Nm (60 It-lb) - mountlng collar
Steering tle rod to steerlng knuckle 65 Nm (48 it-lb)
Strut assembly top to strut tower 24 Nm (18 it-lb)
- - -

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/~ront Susaension
Front suspension arms FRONT SUSPENSION ARMS
Scyllnder models (5251,5281,530i)
Control arms and tension struts are attached to the front sub-
Front suspension arms V-8 models (5401)
frame through rubber bushings and to the steering ltnuckles
by ball joints.
NOTE-
Tension struts are sometimes called thrust arms or thrust
rods.
Control arms or tension struts are sometimes called lower
front arms or lower rear arms.
Inspect ball joints for wear and looseness. lnspect bushings
for wear or fluid
lealts. The ball joint can only be replaced as
part of an entire suspension arm assembly. Some suspen-
sion arm
bushinas are available as re~lacement Darts. Al-
ways replace in pairs
NOTE-
Steering wheel vibration during braking (usually at road
speeds of
50 to 60 m.p.h.) are often causedby faulty suspen-
sion arm bushings, not out-of-true brake rotors.
Some special tools may be required to remove suspension
arms and to replace bushings. Read procedures through be-
fore beginning the job.
Control arm, removing and installing
(6-cylinder models)
- Raise car and remove wheel
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
parfs.
Cars equipped with vertical headlight adjustment system:
Disconnect control arm from level sensor.
Remove control arm fasteners (arrows). Lightly tap inner
control arm mounting bolt out of subframe.