wheels BMW 540i 1998 E39 Owner's Manual

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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

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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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300-1 4
I Susoension. Steerina and Brakes - General
DSC system I
Dynamic Stability Control (DSC)
Dynamic Stability Control (DSC) utilizes many principles and
components of the ASC traction control system. DSC is ac-
tive throughoutthe driving range, unlike ASC which is only ac-
tive during acceleration and braking. DSC helps stabilize the
vehicle in cornering and avoidance maneuvers by adjusting
engine controls such as throttle, ignition, fuel injection and the
application of
brake pressure individually to the wheels.
Inputs
fi- 0
2 4-* .. o
[11-' IJ
411m4
3?-
G
4 The DSC control module uses various inputs to determine
vehicle instability during braking, cornering, or reduced trac-
tion situations. Based upon these inputs the ABSIDSC con-
trol module sends outputs to the engine control module and
the ABSIDSC hydraulic unit to activate torque reduction pro-
tocols and braking intervention.
-
ABSIDSC control module
OUI~YIS
4
The DSC system can be toggled on and off by a switch
mounted on the center console. Turning off the DSC system
does not disable ABS or ASC functions.
+
Measure ride height (A) from center of fender arch to bottom
of wheel rim.
Car in normal loaded position on the ground. See Normal
loaded position.
Engine
control
module
Specified tires and wheels, correct tire pressure, even tire
wear
-'* 9-
.%A
Correct wheel bearing play
T'== ..t, 9 B
-.m
Model with air suspension (EHC): Disconnect electrical har-
ness connector to air supply pump to prevent automatic
height regulation.
When finished, reset ride height using BMW diagnostic
scan tools DIS or
MoDiC.
NOTE-
Airsupply pump is located beneath a cover under the spare
tire in the floor of the cargo compartment.
- If ride height is outside specification listed, install new
springs. Suspension spring removal and installation is cov-
ered in
310 Front Suspension and 330 Rear Suspension.
Normal loaded position
Each front seat 68 kg (150 Ib)
Center of rear seat 68 kg (150 lb)
Trunk 21 kg (46 lb)
Fuel tank full

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31 0-22
I Front Suspension
Stabilizer bar, removing and installing
On E39 models the front stabilizer bar links attach to the strut
assemblies.
- Raise car and support safely.
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 jaclc stands under
suspension parts.
< Remove slaol zer bar connecring I nk rnounl ng nLts (A) from
r~glit and eft s~des of slaol lzer bar C~~nIerhol~ ball ]olnl (6)
with flat wrench
NOTE-
Use a thin wrench to counterhold shaft of stabilizer bar link
ball joint while removing mounting nut.
< Remove stabilizer bar anchor bushing nuts (arrows) on right
and left sides and remove bar.
- Installation is the reverse of removal, noting the following.
Use new self-locking nuts on stabilizer bar links.
Installation of stabilizer bar is easiest with car level (front
wheels at the same height).
Tightening torques Stabilizer bar to stabilizer link
59 Nm (44 ft-lb)
Stabilizer anchor to subframe 22 Nm (16 ft-lb)

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320-7
Steering and Wheel ~liqnmentl
STEERING WHEEL
Steering wheel, removal and installation
WARNING -
The BMWairbag system (Supplemental Restraint System or
SRS) is complex. Special precautions must be observed
when servicing. Serious injury may result if
SRS system serv-
ice is
attempted by persons unfamiliar with the BMW SRS
and its approved service procedures. BMW specifies that all
inspection andservice should be preformed by an authorized
BMW dealer.
E39 cars may come with either one of two different styles of
steering wheel:
Multifunction (MFL) steering wheel
* Sport steering wheel
4 Multifunction (MFL) steering wheel components:
1. Cruise control 1 radio 1 telephone electrical harness
2. Horn button electrical harness
3. Airbag electrical harness
4. Radio / telephone control switch set
5. Air bag
6. Cruise control switch set
Sport steering wheel
3
5 0021413
4 Sport steering wheel components:
1. Switch carrier
2 Steering wheel switch set electrical harness
3. Airbag
4. Lower cover
5. Horn button and airbag electrical harness
- Center steering wheel. Make sure front wheels are pointed
straight ahead.
- Disconnect negative (-) cable from battery.
CA UTIOP&
Prior to disconnecting the battern read the battew discon-
nection cautions given in
001 General Cautions and
Warnings.
-

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i Steering and Wheel Alignment
RACK AND PINION STEERING
(6-CYLINDER MODELS)
Refer to the steering components illustration when perform-
ing the procedures below.
Rack and pinion steering
components
(6-cylinder models)
1. Power steering fluid reservoir
2. Fluid supply line
3. Power steering pump
4. Copper sealing ring
5. Banjo bolt MI4
6. Banjo bolt MI6
7. Power steering rack
8. Fluid return line
9. Pressurized fluid line
10. Steering fluid cooler
11. Rack boot components
12. Tie rod nut
13. Washer
14. Outer tie rod end
15. Tie rod locking ring
16. Outer tie rod end loclc nut
17. Inner tie rod
18. Hydraulic control valve
Steering rack, removing and installing
- Remove steering wheel as described earlier.
- Raise front of car, and remove front wheels.
WARNING -
Male sure 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 splash shield from under engine.
- Remove right and lefl engine mount fasteners
-" ., - , . ,

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Steering and Wheel Alignment
Pitman arm, adjusting
As the vehicle suspension settles down, the toe on the left
and right wheels must remain identical for proper handling.
By adjusting the height of the
pitman arm, the left and right tie
rods are moved to the same ride level setting. This will opti-
mize straight-ahead travel on uneven road surfaces.
- Raise front of car. Remove splash shield from under engine.
WARNING-
Male sure the car is iirmly supported on jack stands de-
signed ior the purpose. Place jack stands beneath structural
chassis points. Do not place
jaclc stands under suspension
parts.
- Remove bolts from left and right inner control arm mounts.
Place
BMW special tool 32 2 140 through right side control
arm mounting bolt hole.
Loosen fastener
A and push pin El up so that it is firmly
against tie rod
(arrow). Tighten fastener A.
- Remove tool without disturbing position of pin El.
- Loosen pitman arm clamping bolt and slide arm up.
4 Place special tool 32 2 140 through left side control arm
mounting bolt hole.
Slide
pitman arm up or down until tie rod makes contact
with pin
(El).
Tighten pitman arm clamping bolt.
Tie rod height differences
Deviation between
left and right tie rod height -?-I .5 rnrn (LO6 in)

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Steerina and Wheel ~lianmentl
Proper handling, stability and driving ease depend upon the
correct alignment of all four wheels. The front axle is aligned
in relation to the rear axle, then the front wheels are aligned in
relation to one another. This is known as a four-wheel or
thrust-axis alignment.
Front and rear alignment specification are given in tables at
the end of this repair group.
BMW E39 cars use a sophisticated multi-link suspension at
the front and rear of the car. Proper alignment requires com-
puterized alignment equipment.
Camber
Front wheel camber is set at the factory and cannot be adjust-
ed. Rear wheel camber is fully adjustable.
Always set rear camber before adjusting toe
Before making rear camber adjustment, install a new rear
control arm mounting nut
(arrow) and tighten.
- Loosen mounting nut one-half to one full turn.
Using eccentric bolt, adjust camber to factory settings.
Tighten nut only after car has been lowered to ground and
suspension has settled.
Tighten nut while counterholding adjustment bolt.
Tightening torque
Camber adjusting nut (rear)
MI2 (sedan)
- MI4 (Sport Wagon)
115 Nm (85 ft-lb)
174 Nm (128 ft-lb)
Caster
Front and rear caster are fixed by the design of the car and
deviations are usually the result of worn or damaged suspen-
sion or body parts.
- Check front suspension arms and bushings for wear, dam-
age and deformation if front caster problems are present.
- Check rear axle subfrarne and traction struts if rear caster
problems are present.

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320-34
I Steerins and Wheel Alignment
Front toe and toe difference angle
Toe is the difference in the distance between the front of the
front wheels and the rear of the front wheels. It is adjusted by
altering the length of the tie rods.
Toe difference angle determines the progressively different
paths taken by the front wheels as the car is turning. In
V-8
models, it is set by the pitman arm adjustment, but depends
on accurate setting of the toe.
Toe adjustments should only be made on specialized align-
ment equipment and only with the car in normal loaded posi-
tion, described below.
- Set front wheel toe at tie rod ends:
4 6-cylinder models: Loosen tie rod lock nut (A).
Adjust toe by turning inner tie rod (B) to change length
- V-8 models: Loosen left and right tie rod clamp bolts.
Adjust toe by turning inner tie rod to change length.
NOTE-
* Steering rack or steering gearbox can be centered by
aligning centering mark on steering shaft
with lug on steer-
ing rack.
To keep steering wheel centered, adjust both tie rods equal
amounts.
&cylinder models: Make sure the rubber boot on the rack
moves freely on the tie rod and does not become twisted.
Tightening torques
Tie rod clamp bolt
Tie rod collar
nut
27 Nm (20 ft-lb)
45 Nm (33 A-lb)
Rear toe
To adjust rear wheel toe, turn eccentric inner mounting bolt in
upper front control arm (traction strut).
NOTE-
Always adjust rear camber first.
- Before making toe adjustment, install new
mounting nut and tighten.
- Loosen nut one-half to one full turn.
4 Turn eccentric bolt (arrow) to adjust toe. rear
control arm

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Steering and Wheel Alignment
- Tighten nut while counterholding adjusting bolt,
- Tighten nut only after car has been lowered to ground and
suspension has settled.
Preparing for alignment
- The following conditions are necessary prior to wheel align-
ment:
Correct wheels and tires are installed, in good condition,
and are at the correct inflation pressures.
All steering and suspension parts and bushings are un-
damaged and show no signs of abnormal wear. Wheel
bearings are in good condition.
Ride height is in accordance with specifications. See
300
Suspension, Steering and Brakes-General.
Car is in normal loaded position. See below.
* Cars with air suspension: Remove air suspension power
fuse.
Normal loaded position
Each front seat
68 Kg (I50 lb)
Center of rear seat
Trunlc
Fuel tank
68 Kg (150 lb)
21 Kg (46 lb)
Full
Alignment specifications tables
In the alignment specification tables that follow, reference is
made to the various types of suspension used in
E39 cars.
The type of suspension can be identified by loolting at the la-
bel on the front strut tube.
Identifying symbol
None
Solid circle
Solid triangle
M5
Circle
Triangle Version
Standard suspension
Sports
suspension
Sports suspension
M sport package
Standard suspension
Sports suspension Model
Sedan
6-cylinder sedan
V-8 sedan
V-8 sedan
Touring (Sport Wagon)
Touring (Sport Wagon)