1998 BMW 540i Ac system

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Steering and Wheel ~lignmentl
Remove lower steering column flexible joint pinch bolt (ar-
row). Pull flexible joint off steering rack shaft.
Remove steering rack mounting bolts. Remove steering
raclc
from subframe by pulling it to left.
Installation is reverse of removal, noting the following:
Make sure all thread bores, bolts, nuts, splines and mating
surfaces are clean.
Use new steering rack mounting bolts. Tighten in two stag-
es. Note tightening instructions in torque table below.
Use anti-seize paste on inner tie rod threads.
Use new self-loclting nuts wherever applicable.
Use keved
comDonents to reassemble steerino column
flexible\oint to ;teering raclt shaft. u
Use new bolt at steering shaft coupling.
Use new sealing O-rings on banjo fittings.
Do not over-torque banjo bolts.
Fill and bleed power steering system as described earlier.
Use tie rod measurement previously made (measurement
A) to temporarily set toe.
Have car professionally aligned.
Tightening torques Hydraulic lines to steering rack (use new O-ring
seals)
M14 banjo bolt 35 Nrn (26 ft-lb)
. M16 banjo bolt 40 Nm (30 ft-lb)
Steering shaft coupling
to rack (use new bolt) 19 Nm (14 it-lb)
Steering rack to subframe (use new bolts)
- initial torque 50 Nm (37 ft-lb)
Torque angle 90"
Tie rod
to Steering knuckle (replace self-locking
65 Nm (48 ft-lb)
nut)
- to Steering rack 71 Nm (52 ft-ib)
Outer tie rod end lock nut
51 Nm (38 ft-lb)

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Steering and Wheel Alignment
Tightening torques
Tie rod
to Steering knuckle (replace self-locking nut) 65 Nm (48 it-lb)
to Steering rack 71 Nrn (52 ft-lb)
Outer tie rod end lock nut 51 Nrn (38 ft-lb)
Refer to the steering components illustration when perform-
ing the procedures below.
Steering gearbox system
components
(V-8 models
up to
911 999)
1. Tie rod end nut
2. Washer
3. Tie rod end
4. Steering fluid cooler
5. Tie rod end clamp bolt
6. Nut
7. ldler arm
8. ldler arm bushing
9. ldler arm bolt
10. Steering fluid reservoir
11. Hose clamp
12. Fluid supply line
13. Power steering pump
14. Fluid return line
15. O-ring seal
16. Banjo bolt
17. High pressure line
18. Center tie rod
19. Nut
20. Pitman arm
21.
Pitman arm pinch bolt
22. Nut
23. Fluid cooler supply line
24. Steering gearbox

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Steering and Wheel ~li~nrnentl
Steering gearbox, removing and installing
- Disconnect negative (-) battery cable. See 020 Mainte-
nance.
CAUTION-
Prior to disconnecting the battew read the battery discon-
nection cautions given in
001 General Cautions and
Warnings.
- Remove airbag unit from steering wheel. See 721 Airbag
System (SRS).
WARNING -
Improper handling of the airbag could cause serious injury
Store the
airbag with the horn pad facing up. If stored lacing
down, accidental deployment couldpropel it violently info the
air, causing
injuv
- Remove steering wheel as described earlier.
- Drain power steering system reservoir.
- Raise front of car.
WARNING -
Make 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
Darts.
- Remove heat shield from left side of subframe.
- Remove fluid hoses from top of steering gearbox. Immedi-
ately plug all fluid openings.
Remove and discard
pitman arm self-loclting nut (arrow).

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L.. Steering and Wheel ~li~nrnentl ~
4 Mark A on steering gearbox shaft must be located in center
of
pitman arm slot.
- Adjust pitman arm as described later.
I 5"?~~5~"
I / < Gap A = 0.5 - 8.5 mm (0.02 - 0.33 in)
- Tighten pitman arm pinch bolt to specification.
' 1 Tightening torques
I u "steering Steering gearbox to subframe 62 Nm (46 ft-lb)
box Steering shaft universal joint to steering 19 Nm (14 It-lb)
gearbox (replace bolt)
- Install center tie rod to pitman arm using a new self locking
Pilrnan nut. arm
5nz3zn588 - Connect harness connector for Servotronic electro-hydraulic
regulator
if necessary.
- Connect fluid hoses to steering gearbox. Use new sealing
washers at couplings and make sure not to overtorque banjo
bolts.
Tightening torques Hydraulic lines to steering gearbox (banjo bolts)
MI0 12 Nm (9 ft-lb)
- M14 35 Nm (26 ft-lb)
. M16 40 Nm (30 ft-lb)
MI8 45 Nm (33 it-lb)
Center tie rod to pitrnan arm 65 Nm (48 it-lb)
(use new self-loclting nut)
- Reconnect negative (-) battery cable.
- lnstall airbag unit. See 721 Airbag System (SRS).
- Fill and bleed power steering system as described earlier.

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330-2
I Rear Suspension
This repair group covers removal and replacement of E39
rear suspension components. A general description of sus-
pension systems and ride height specifications can be found
in 300 Suspension, Steering and Brakes - General.
CAUTIOI\C
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
sparl~s from grinding/cutting op-
erations.
* Do not subject to steel welding splashes.
0 Do not expose to temperatures over 80°C (176°F).
even for shortperlods. Temperatures in painting facili-
ties are not a problem.
Special tools
Special service tools are required for some of the work de-
scribed in this repair group. Most of these tools are special-
ized press jigs and pullers that might be replaced by standard
pullers of various sizes.
Read the procedures through before beginning any job.
< Strut upper mounting nut socket
(Tool No. BMW
31 2 21 0)
I Axle shaft removal and installation set
Spring compressor (Tool No. BMW
31 3 340.31 3 350)

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--
C. -- -- - -- Rear ~us~ensionl
Depending on year and model applications, the Sport Wagon
rear suspension may be equipped with:
Conventional shock absorbers and coil springs
Electronic height control (EHC) system which incorporates
air springs
NOTE-
. Suspension and EHC troubleshooting is covered in 300
Suspension, Steering and Brakes-General.
EHC system repairs, other than air spring replacement,
are covered in Electronic height control
(EHC) compo-
nent replacement.
Replace shock absorbers and springs in pairs only.
Rear shock absorber, removing and
installing
- Raise car and remove rear wheels,
WARNING-
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 parts.
CAUTION-
If working on a vehicle with compressedairshock absorbers,
disable air supply pump by disconnecting electrical plug be-
fore performing any repairs. Pump is located beneath a cover
under the spare tire in the floor of the cargo compartment.
- Support swing arm from below
CAUTIOG
The shock absorber prevents the drive axle and wlieel bear-
ing carrier from dropping too far. Supporting the wheel bear-
ing carrier before disconnecting the shock absorber
mounting fasteners prevents damage to the
brake hose,
parking
brake cable and drive axle CVjoints.
- Working in cargo compartment, remove carpet. Remove tri-
angular upper shock mount covers located beside spare tire
well.
- If applicable: Detach air supply line from shock absorber.
Plug ports and lines to keep out dirt.

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330-1 1
Rear Suspension
Coil spring, removing and installing
Raise car and remove rear wheels.
WARNING-
Make sure 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.
- Remove brake caliper and brake disc. Hang brake caliper
aside with stiff wire. Do not disconnect
bralte fluid hose. See
340 Brakes.
- Remove exhaust system. See 180 Exhaust System.
- Disconnect driveshafl from final drive. See 260 Driveshaft.
- Detach parking bralte cables from mounting bracltets on sub-
frame.
< Support final drive unit from below using transmission jack
and
BMW special tool 33 4 390 or equivalent.
Remove rear suspension
subframe mounting bolts (arrows).
Lower rear
subframe until coil springs can be removed.
When reinstalling springs, replace upper and lower spring
pads if necessary.
Slowly lift suspension
back into position, making sure coil
springs are correctly seated in upper and lower spring seats.
Install and tighten
subframe mounting bolts. Note that on
each bolt, rubber-coated detent plate (arrow) must be in-
stalled at rear in driving direction
- Remainder of installation is reverse of removal
Tightening torques Road wheel
to hub 12OilO Nm (89i-7 ft-lb)
Subframe to body 163 Nm (120 ft-lb)

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Rear Suspension
Air spring, removing and installing
CAUTION-
If vehicle is driven with airspring depressurized, the airspring
will be permanently damaged and must be replaced.
An air spring is made from a flexible rubber material which
forms an airtight cavity. It is pressurized by an air supply
pump activated by an electronic control unit to provide a
vari- . . able spring rate depending on vehicle load
CAUTIOIG
Disable air supply pump by disconnecting electrical plug
before performing any repairs. Pump is located beneath a
cover under the spare tire in the floor of
the cargo compart-
ment.
When removing and installing air connections, extreme
cleanliness must be followed. Small dirt particles can
cause leakage in the system.
Remove luggage compartment floor mat.
- Working above air spring, loosen quick coupling screw con-
nection to allow
air pressure to escape.
- Once pressure has been reduced, retighten screw.
Tightening torque Quick coupling screw
to air pump 2 Nm (18 in-lb)
- Remove quick coupler. Plug openings to keep dirt out,
- Remove air spring mounting clips.
- Raise car and remove rear wheels.
Make sure 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.
- Working underneath rear suspension, lift wheel bearing car-
rier to relieve rear spring tension. Then unbolt air spring
mounting bolt from seat on wheel bearing carrier. Remove air
spring.
NOTE-
Left and right air springs are different. The left air spring is
marked with a red identification
marl. The right air spring is
marked with a blue identification mark.