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1 Driveshaft
Further inspection requires removal of the driveshaft. Checlc
the front centering guide on the transmission output flange for
damage or
misalignment. Also check runout at the transmis-
sion output fiange and output shaft, and at the final drive input
fiange. Check the bolt hole bores in the flange for wear and
elongation.
Driveshaft flange
runout (max. allowable)
Transmission
flange
- Axial play 0.10 mm (0.004 in.)
Radial play 0.07
mm (0.003 in.)
Spin the driveshaft center bearing and
check ior smooth op-
eration without play. Check the constant velocity joint
forwear
or play. Checlc the universal joint for wear or binding. If it is
difficult to move or binds, the driveshaft section should be
replaced.
Universal joint
play
Maximum allowable 0.15
mm (0.006 in.)
NOTE-
With the driveshaft installed, the actual amount that the drive-
shaftjoint pivots is limited. For the most accurate test, check
joint
in its normal range of movement.
If inspection reveals nothing wrong with the driveshaft, it may
need to be rebalanced. This can be done by a speciality drive-
shaft repair shop. Also,
checlc driveshaft alignment as de-
scribed below.
NOTE-
Minor driveshaft vibrations can often be corrected simply by
disconnecting the driveshaft at the final drive and reposition-
ing it go", 180" or 270" in relation to the final drive input
flange.
The troubleshooting table below lists symptoms
oi driveshaft
problems and their probable causes. Most of the repair infor-
mation is contained within this repair group. There are refer-
ences to other repair groups, where applicable.
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Driveshaft
Repair kits for the universal joint are not available for BMW
driveshafts.
A worn or damaged universal joint usually require
replacement of the driveshaft.
The driveshaft is balanced to close tolerances. Whenever it is
to be removed or disassembled, the mounting flanges and
driveshaft sections should be marked with paint or a punch
before proceeding with work. This will ensure that the
drive-
shaft can be reassembled and installed in exactly the original
orientation.
1. Rear section of drive shaft
2. Hex bolt, MI2 x 1.5 x 25
3. Knurled bolt
4. Clamp
5. Reinforcement
6. Seal
7. Constant velocity joint
8. Circlip
9. Hex nut
10. Hex bolt, M12x 1.5~58
11. Centering sleeve
12. Flexible disk
13. Self-locking hex nut
14. Front section of driveshaft
15. Center bearing
16. Dust cover (some models)
17. Spacer (some models) -
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300 Suspension. Steering and Brakes .
Genera8
General ........................... .30 0.2
Aluminum suspension components
...... .30 0.2
Front Suspension ................. .30 0.2
Front suspension 6-cylinder models
(525i.5281. 530i) ..................... .30 0.3
Front suspension V-8 models (540i) ...... .30 0.4
Rear Suspension .................. .30 0.5
Sedan models
....................... .30 0.5
Rear suspension sedan models ........ .30 0.6
Sport Wagon models ................. .30 0.6
Rear suspension Sport Wagon
(with coil springs)
.................... .30 0.7
Rear suspension Sport Wagon
(EHC with air springs)
................. .30 0.8
EHC operational diagram .............. .30 0.9
Steering ......................... .30 0.10
Rack-and-pinion steering ............. .30 0.10
Recirculating ball and nut steering ...... .30 0.10
..................... Brake System 300-10
Wheels and Tires ................. 300-1 1
............... Rim and tire sizes table 300-1 1
Electronic Brake and Stability
.................. Control Systems 300-1 1
E39 electronic brake and stability
........ control systems application table 300-12
........................ ABS system 300-1 2
Automatic Stability Control (ASC)
....... 300-12
ABSIASC traction control system ....... 300-13
Dynamic Stability Control (DSC)
........ 300-14
Ride Height ....................... 300-14
......... Front ride height specifications 300-1 5
......... Rear ride height specifications 300-16
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[~us~ension, Steering and Brakes - General
This section of the manual covers front and rear suspension,
braking and steering systems, and contains wheel, tire and
wheel alignment information and specifications. Also covered
here are the integrated braking and suspension systems in-
cluding
antilock braking (ABS), traction control (ASCIDSC),
and electronic height control (EHC).
Vehicle ride height information is at the end of this repair
group. Alignment information is in
320 Steering and Wheel
Alignment.
Aluminum suspension components
In order to reduce vehicle weight, aluminum suspension com-
ponents are used in some models. A test with a magnet will
easily reveal the metal used. If working with aluminum com-
ponents, be sure to read and follow the cautions below.
CAUTION-
* Due to the chemical and corrosion characteristics of alumi-
num, do not bring into contact with battery acid.
Do not use wire brushes with brass or iron bristles.
Only use brushes with stainless steel bristles.
Do not expose to flying sparks from
grinding/cutting op-
erations.
Do not subject to steel welding splashes.
Do not expose to temperatures over
80°C (176"F),
even for short periods. Temperatures in painting facili-
ties are not a problem.
The E39 front suspension subframe is used as a rigid mount-
ing platform for the front suspension arms, stabilizer bar and
steering gear.
The suspension arms, known as the lower control arms and
the tension struts (thrust arms), are connected to the
sub-
frame through rubber bushings. The arms are connected to
the steering
knucltles in a double pivot configuration.
Each front strut assembly includes a tubular strut and a coil
spring. The upper strut mount includes a bearing. The lower
end of each strut housing is fitted to the steering knuckle. The
integral wheel bearing and hub are bolted to the steering
Iknucltle.
6-cylinder and V-8 models use different steering systems and
other front suspension components.
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300-5
Suspension, Steering and Brakes - ~enerall
The E39 rear suspension subframe is used as a rigid mount-
ing platform
forthe differential (also called final drive) and rear
suspension components. The differential is mounted to the
subframe and the subframe is bolted to the body through rub-
ber bushings which help isolate drivetrain noise and vibration.
The
€39 rear suspension is known as a modified multi-link
system. Three control arms on each side locate the rear
wheels.
The lowercontrol arm, called the swing arm, is attached to the
wheel bearing carrier through a pivoting integral link.
An eccentric mounting bolt at the rear inner mounting of the
swing arm is used for rear camber adjustment.
The inner end of the upper front control arm, called the trac-
tion strut, is also mounted with an eccentric fastener, used to
adjust rear toe.
Drive axles with constant-velocity (CV) joints at both ends
transfer power
from the differential to the road wheels.
Sedan models
The rear suspension in sedan models uses coil springs over
strut shock absorbers. The bottom of each strut bolts to the
wheel
carrier.The top strut mount attaches just below the rear
parcel shelf of the car.
Sedan models fitted with EDC (Electronic Dampening Con-
trol) use air struts.
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300-6
/Suspension, Steering and Brakes - General
Rear suspension sedan models
Coil spring
Strut
-
'01 arm
Sport Wagon models
In order to provide a wide, ilat iloor in the cargo compartment,
the rear suspension on the Sport Wagon is unique to itself.
The shoclcabsorber is attached diagonally between the lower
swing arm and a mounting bracket on the subframe. The
spring on each side is mounted between a perch at the top
oi
the wheel bearing carrier and the bottom of the cargo com-
partment floor.
Starting with
1999 Sporl Wagon models, a self-leveling air
suspension system with electronic height control (EHC) was introduced. The system is standard on
V-8 models and op-
tional on 6-cylinder models.
On models fitted with electronic height control (EHC) rear
suspension, the standard coil springs are replaced by air
springs. Air pressure in the air springs is automatically con-
trolled by the
EHC system to compensate for ride height and
load variations.
Page 628 of 1002
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300-8
Suspension, Steering and Brakes - General
Rear suspension Sport Wagon
(EHC with air springs)
Air sprIn9 Shock absorber I
(tiaction strut) arA
(lower control arm) Integral arm 502330210
EHC initiates a control sequence as necessary. The system
offers the following features:
Control system independent from vehicle engine (no en-
gine driven hydraulic pump system)
Individual control of rear wheels
Uneven load identified and compensated for
Uneven road surfaces identified and not compensated for
Automatic control interrupted when cornering
System diagnosable using the
BMW Service Tester (DIS-
plus, GTI, or MoDiC)
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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