front suspension BMW 540i 1998 E39 Repair Manual

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330-39
I Rear suspension1
- Remainder of installation is reverse of removal, noting the fol-
lowing.
Models with coil springs: Fit spring correctly in lower spring
seat.
* Models with air suspension: Fit eccentric lug at bottom of
air spring in recess of wheel carrier spring seat.
Always use new self-locking nuts.
- Make sure all threaded bolts, nuts and mating surfaces are
clean.
a Tighten fasteners to final torque only after vehicle has
been lowered and suspension has settled.
Stake axle collar nut afler tightening.
Tightening torques
ABS pulse sensor to wheel bearing 8 Nm (6
ft-lb)
carrier
Air spring to wheel bearing carrier 20 Nm (15 ft-lb)
Brake rotor to hub 16 Nm (12
it-lb)
Rear axle shaft to hub (M27) 300 Nm (221 ft-lb)
Rear brake pad carrier (caliper) to wheel 65 Nm (48 ft-lb)
bearing carrier
Road wheel to hub
120ilONm
(89 k7 ft-lb)
Swing arm to wheel bearing carrier 256 Nm (189 it-lb)
Upperfrontcontrol arm (traction strut) to 65 Nm (48 ft-lb)
wheel carrier
Upper rear control arm to wheel carrier 142 Nm (105 ft-lb)
Rear wheel bearing, replacing
< The rear wheel bearing is integrated with its mounting flange.
1. Torx bolt
2. Wheel bearing and mounting flange
3. Wheel hub
4. Collar nut
- Raise rear end of car and remove wheel.
WARNING -
Make sure the car is firmly supported on jaclc stands de-
signed for the purpose. Place jack stands underneath struc-
tural chassis points. Do not place jack stands under
suspension parts.

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Final Drive
Final drive, removing and installing
- Raise rear of car.
WARNING-
Make sure that the car is firmly supported on jack stands de-
signed for the purpose. Place the jaclc stands beneath struc-
tural chassis
~oints. Do not i lace iaclc stands under
( suspension barfs.
Remove exhaust system. See 180 Exhaust System.
Disconnect drive shaft from final drive. See
260 Driveshaft.
Remove drive axle CV joint bolts (arrows) at left and right
sides. Suspend drive axles from body using stiff wire.
4 Support final drive with BMW special tool 33 4 390.
* Remove front final drive mounting bolt.
Remove rear final drive mounting bolts
(2).
Carefully lower final drive unit.
- To install, use BMW special tool 33 4 390 to lift final drive into
place.
CA UTIOP&
The following sequence must be used when installing the fi-
nal drive to prevent torsion stress on the final drive during in-
Install mounting bolts and finger tighten only.
Remove final drive support.
Tighten both rear mounting bolts.
Tighten front mounting bolt.
NOTE-
Use new self-locking nuts.
- Check differential oil level. See Differential oil level, check-
ing.
- Remainder of installation is reverse of removal.

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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

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340-6
1 Brakes
Brake system troubleshooting
/symptom I Probable cause 1 Repairs
Brake squeal
Pedal goes to floor when
bralting
Low pedal after system bleeding
Pedal spongy or brakes work
only when pedal is pumped
Excessive braking effort
Brakes pulsate, chatter or grab
Uneven
bralting, car pulls to one
side, rear braltes
loclt
Brakes drag, bind or overheat Brake
pad carriers dirty or corroded or
pads loose (poor fit) in pad carrier
Braite pads heat-glazed or oil-soaked
Wheel bearings worn (noise most
pronounced when turning)
Incorrectly Installed brake pads,
parking bralte shoes, or bralte parts
Brake fluid loss due to system leaks
Master cylinder or traction control
system faulty
Master cylinder faulty
Air in braite fluid
Master cylinder or traction control
system faulty
Brake pads wet
Brake pads
heat-glazedorfluid-soalted
Vacuum booster or vacuum hose
connections to booster faulty
--- Warped brake rotors
Brake pads worn
Brake pads heat-glazed or oil-soaked Remove
brake pads and clean calipers. Use original
equipment pads for proper fit and use BMW anti-squeal
compound during installation,
Replace brake pads. Ciean rotors. Replace leaking caliper:
as required.
Replace worn bearings. See 310 Front Suspension
or33C
Rear Suspension.
Check component installation. Checldreplace anti-rattle
springs.
Checlt fluid level and inspect for signs of leakage.
Replace master cylinder. Diagnose traction control system
using factory or compatible diagnostic tool.
Replace master cylinder.
Bleed system using factory or compatible diagnostic tool.
Replace master cylinder. Diagnose traction control system
using factory or compatible diagnostic tool.
Use light pedal pressure to dry pads while driving.
Replace
bralte pads and rotors. Replace leaking calipers.
lnspect vacuum lines. Test vacuum booster and replace as
required. Test vacuum non-return valve for one-way flow.
Resurface or replace rotors.
Replace brake pads.
Clean rotors. Replace leaiting calipers.
Incorrect tire pressures or worn tires
Brake pads on one side of car heat-
glazed or fluid-soaked
Caliper or brake pads binding
Worn suspension components
Brake caliper or brake pads binding
Master cylinder or traction control
system faulty lnspect
tire condition. Checlt and correct tire pressures.
Replace brake pads. Clean rotors. Replace leaking
calipers.
Clean and recondition brakes.
Inspect for worn or damaged suspension components. See
310 Front Suspension or 330 Rear Suspension.
Ciean or replace caliper.
Replace master cylinder. Diagnose traction control system
using faclory or compatible diagnostic tool.

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340-1 2
Brakes Brake pads, checking and replacing
Brake pads can be replaced without disconnecting the brake
fluid hose from the caliper or having to bleed the brakes. The
rotors can be replaced without disassembling wheel hub and
bearing. Always machine or replace rotors in pairs. Replace
pads in sets.
Front and rear brake pad replacement procedures are identical.
WARNING -
* Altllough semi-metallic andmetallic brale friction materials
in brake pads or shoes no longer contain asbestos, they
produce dangerous dust.
Treat all
brale dust as a hazardous material.
Do not create dust by grinding, sanding, or cleaning
brake friction surfaces with compressed air.
CAUTION--
Pressing caliper piston in may cause brake fluid reservoir to
overflow To prevent this, use a clean syringe to first remove
some fluid
from reservoir.
Raise car and remove 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 jack stands under suspension
parts.
/ 4 To measure brake pad lining thickness, insert BMW special
n 1 tool 34 1 260 at either frontilght wheel or left rear wheel -
Move wheel until notch for brake wear indicator can be
seen through wheel opening.
Insert tip of tool into notch so that the body of tool rests on
brake pad backing plate
(A), and tip touches bralte disc
(B).
Replace pads if thickness is 3.0 mm (0.12 in) or less.
Pry off
bralte calipe~ , anti-rattle spring (arrow).

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340-1 5
Brakes
- Remainder of installation is reverse of removal.
- Clean brake caliper mounting bolts (7 mm Allen). Replace
ones which are not in perfect condition. Do not grease.
Top up brake fluid to MAX marking.
- Before driving car, pump bralte pedal several times so that
brake pads contact brake rotors.
Check that brake fluid level is correct. Top up if necessary.
Hold ignition key for at least
30 seconds in accessory po-
sition without starting engine. This clears any fault codes in
memory and turns off brake pad warning light.
Tightening torques Brake caliper to pad carrier
(7 mm Allen)
Front caliper
30 Nm (22 It-lb)
- Rear caliper 28 Nm (21 It-lb)
Road wheel to hub
120i 10 Nm (89i7 ft-lb)
Brake rotors, removing and installing
- Raise car and remove wheels
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 jack stands under suspension
parts.
Remove brake caliper carrier bolts (arrows). Suspend brake
caliper from chassis using stiff wire.
NOTE-
Hydraulic brake line remains connected.
4 Remove bralte rotor mounting screw (arrow) and remove ro-
tor.
- Inspect rotor for cracks, signs of overheating and scoring.
- Minimum allowable thickness (MIN TH) is stamped on rotor
hub. Measure rotor braking surface with a micrometer at
eight to ten different points and use the smallest measure-
ment. Compare to specifications in table below.
- If rotor does not pass minimum thickness requirements or is
damaged, replace rotor.

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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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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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Body shell
Exterior and aerodynamics
Crash behavlor -frontal impact
-side impact
Body
-rear impact Structural body components -rigidity
-rollover -strength -vibrations -acoustics
Bumpers compartment lid -bendable Seets,.steerlng system .dents -vibrations bars -vibration patterns
Fenders -aerodvnamic
With its traditional styling features, such as the ltidney grille.
circular headlights behind a glass cover (for reasons of
streamlining), and the
"kiclt" in the rear most roof pillar (C-pil-
lar), the E39 can be immediately recognized as a BMW.
The BMW 5 Series chassis is a unibody design constructed of
high strength steel. Attaching parts, such as the front fenders,
rear quarter panels, doors,
trunk lid and hood are also con-
structed of
steel.
Computer aided design (CAD) techniques have been used in
refining the
E39 body to reduce vehicle weight while retaining
strength and increasing torsional rigidity. For good handling
purposes, the more rigid the structure the more precisely the
suspension can operate.
Wind resistance
Windows bonded flush to the body and the guided flow of
cooling air into the engine compartment provide the
carwith a
good coefficient of drag (Cd).
E39 cars have been designed
for balanced aerodynamics but not necessarily an extremely
low Cd. See table below.
Windshield wipers are designed for effectiveness at speeds
up to and beyond 200
ltph (124 mph).
Coefficient of aerodynamic drag (Cd)
6-cylinder sedan 0.30
V-8 sedan 0.31
6-cylinder Sport Wagon 0.31
V-8 Sport Wagon 0.33
Fenders
The exterior panels are corrosion-resistant zinc coated (gal-
vanized) steel. The front fenders are bolted on. For front fend-
er replacement information, see
410 Fenders, Engine
Hood.

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400-4
I Bodv-General
Bumpers
The front and rear bumpers are clad in high quality
deform-
able plastic and, at solid barrier impact speeds of 4 kph (2.5
mph), provide protection with virtually no damage to the
bumper
orthe vehicle. In addition to hydraulic dampeners.
which absorb the initial impact energy, these bumpers are
backed by compressible tubes. These deform in a controlled
manner at impact speeds greaterthan that
forwhich bumpers
and hydraulic dampeners are designed. This helps avoid ex-
pensive damage to the body at impact speeds up to 14 kph (9
mph).
The E39 Sport Wagon was introduced to the US market in
911 998 (model year 1999). It shares many components with
the E39 sedan and is identical to it from the B-pillar forward.
US
marltet 5 Series Sport Wagons are available in two vari-
ants:
6-cylinder
(5251, 528i) powered by the 2.8 liter M52 TU en-
gine (1 999) or the 2.5 liter M54 engine (2000 and later)
* V-8 (540i) powered by the 4.4 liter M62 TU engine
The wheelbase of the Sport Wagon is the same as the sedan.
Howeverthe body is 30
mm (1.2 in) longer and 10 mm (0.4 in)
higher.
The Sport Wagon rear suspension was redesigned to elimi-
nates the upper rear spring strut mounting on the E39 sedan.
The use of separate coil springs and
shoclc absorbers results
in a flat, wide floor in the cargo area. See
300 Suspension,
Steering and Brakes-General.
The self-leveling air spring suspension system (electronic
height control or EHC) is standard on Sport Wagon V-8 mod-
els and optional on 6-cylinder models.
Sport Wagon cargo capacities are shown below.
Sport Wagon load capacities
Cargo capacity
Rear seat up 909 liters (32.1 cu ft)
Rear seat folded down I809 liters (63.9 cu ft)
Load limit
Cargo compartment
460 Kg (1014 lb)
Roof
I00 Kg (220 lb)