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I Steerina and Wheel Alianment
Steering
system
Two types of steering gear are used in the E39 series models.
6-cylinder
(5251, 528i and 530i) models are equipped with
rack and pinion steering. The steering rack is mounted to
an aluminum subframe.
V-8
(540i) models are equipped with a recirculating ball
and nut steering gearbox mounted to a steel subframe.
At low speeds, maximum power assist is provided to ease
parking and city driving. At high speeds, assist is reduced to
ensure stability. The power steering system varies assist
based on engine speed.
Power boost for the steering is provided by an engine-driven
hydraulic pump. A hydraulic control valve is used to control
boost pressure.
The steering wheel connects to the steering gear via an ad-
justable steering column which incorporates a rubber cou-
pling ("guibo") to dampen vibration and noise.
Power steering fluid is supplied from the fluid
reservoir to the
pump and to the steering gear via rubberlmetal hoses.
The return line from the steering gear to the
reservoir loops
into the airstream in front of the radiator and connects to the
steering fluid cooler. The fluid cooler is attached to a cassette
which also includes cooling coils for engine oil, transmission
fluid and AIC condenser.
The steering gear requires no maintenance other than align-
ment and periodic inspection for worn components. Inspect
rubber rack boots
(rack and pinion system) and tie-rod end
boots periodically for tears or damage. Replace
if necessary.
-
NOTE-
The airbag system is traditionally referred to as Supplemen-
tal Restraint System (SRS). The
BMW versfon of SRS used
m the E39 models is known as the Multiple Restraint System - (MRS). - -

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Steering and Wheel Alignment
Steering system warnings and cautions
WARNING -
The BMW airbag system is complex. Special precautions
must be observed when servicing the system. Serious in-
jury may result if system service is attempted by persons
unfamiliar with the BMW
airbag system and its approved
service procedures. BMW specifies that all inspection and
service should be
peiformed by an authorized BMW deal-
e,:
The BMW E39 is equipped with an airbag mounted in
the steering wheel. The
airbag is an explosive device
and should be treated with extreme caution. Always fol-
low the
airbag removal procedure as outlined in 721
Airbag System (SRS).
BMW airbags are equipped with a bacli-up power sup-
ply inside the
airbag control module. A 5 second wait-
ing period should be observed after the battery cable
has been disconnected. This will allow the reserve
power supply to discharge.
Do not reuse self-locking nuts. They are designed to
be used only once and may fail if reused. Always re-
place them with new locliing nuts.
* Do not install bolts and nuts coated with undercoating
wax, as correct tightening torque cannot be assured.
Always clean the threads with solvent before installa-
tion, or install new parts.
Do not attempt to weld or straighten any steering com-
ponents. Always replace damagedparts.
CAUTION--
- Some E39 models are equipped with aluminum suspen.
sion components. The following cautions apply:
Due to the chemical and corrosion characteristics of
aluminum, do not bring into contact with battery acid.
Do not clean with wire brushes with brass or iron bris-
tles. Only use brushes with stainless steel bristles.
Do
not expose to flying sparks from grindinghutting op-
erations.
Do not subject to steel welding splashes.
* Do not expose to temperatures over 80% (176°F).
even for short periods. Temperatures in painting iacili-
ties are not a problem.

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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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320-8
Steering and Wheel Alignment
4 MFL steering wheel: Loosen 2 airbag mounting fasteners
(Torx T27 or T30) located at rear of steering wheel (arrow).
4 Sport steering wheel:
Insert screwdriver through opening in rear of steering
wheel and push against spring tension to release
airbag.
Repeat procedure on other side of steering wheel.
- Carefully lift airbag from steering wheel and disconnect elec-
trical harnesses from
back side of unit. Refer to component
illustrations above. Also see
721 Airbag System (SRS).
Improper handling of the airbag could cause serious injury.
Store the
airbag with the horn pad facing up. If stored facing
down, accidental deployment couldpropel it violently into the
Avoid damaging the variety of convenience switches, such
as radio and cruise controls, installed in the steering wheel of
4 Remove steering wheel center bolt (arrow).

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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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I Steering and Wheel Alignment
I I 4 Gap A = 0.5 - 8.5 mm (0.02 - 0.33 in)
- Reinstall inner control arm bolts
Tightening torques
Control arm to
subframe 78 Nm (58 it-lb)
(tighten with wheel on ground)
Pitman arm pinch bolt (note direction of threads) 61 Nm (45 ft-lb)
Steering idler arm, removing and installing
The idler arm is bolted to the subframe through a bushing.
The bushing is subject to wear and is available as a replace-
ment part.
- Raise front of car. Remove splash shield from under engine.
WARNING -
Male sure the car is firmly supported on jaclc stands de-
signed for the purpose. Place jack stands beneath structural
chassis points. Do not place jack stands under suspension
parts.
4 Remove center tie rod fastener and press tie rod out of idler
arm with
BMW special tool 32 1 190.
- Remove idler arm mounting bolt through opening in sub-
frame and remove idler arm from car.
- Installation is reverse of removal.
Make sure all thread bores, bolts, nuts and mating surfac-
es are clean.
Use new self
loclting nuts to mount idler arm to subframe
and center tie rod to idler arm.
If idler arm or idler arm bushing is replaced, adjust
pitman
arm as described earlier.
Have car professionally aligned.
Tightening torques
Center tie rod to idler arm 65 Nm (48 ft-ib)
(replace self-locking nut)
Idler arm to front subirame
(replace self-locking nut) 62
Nm (46 it-lb)

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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.