height BMW 540i 1997 E39 Owner's Manual

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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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[Rear Suspension Swing arm, removing and installing
(sedan models)
CAUTION-
If working on a vehicle with compressed airshock absorbers,
disable air supply pump by disconnecting electrical plug be-
fore performing any repairs.
- Raise rear end of car and remove wheel
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
sus~ension Darts.
- Disconnect control rod for ride height sensor if applicable.
Remove
ABS pulse sensor (arrow) from wheel bearing car-
rier.
Remove stabilizer bar link mounting nut
(arrow). Press link
out of swing arm.
4 Mark location (arrow) of rear camber adjustment washer and
bolt.
NOTE-
Rear camber is adjusted at the inner swing arm eccentric
rear mounting bolt
- Support wheel bearing carrier from below.

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Rear ~us~ensionl
Working in cargo compartment, attach BMW special tools
33 2 302,33 2 303 and 33 2 305 to special tool 33 2 304.
Use special tool 33 2 306 to compress spring.
Tighten until lower spring coil lifts off spring seat on wheel
bearing carrier.
- Disconnect control rod for ride height sensor if applicable.
4 Remove ABS pulse sensor (arrow) from wheel bearing car-
rier.
- Support wheel bearing carrier from below.
CAUTION-
The shock absorberprevents the drive axle and wheel bear-
ing carrier from dropping too far. Supporting the wheel bear-
ing carrier before disconnecting the shock absorber
mounting fastenerprevents damage to the
brake hose, park-
ing brake cable and drive axle
CVjoints.
- Remove shock absorber lower mounting bolt
4 Remove stabilizer bar link mounting nut (arrow). Press link
out of swing arm.
4 Mark location (arrow) of rear camber adjustment washer and
bolt.
NOTE -
Rear camber is adjusted at the inner swing arm eccentric
rear mounting bolt.

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330-27
Rear ~uspensionl
- If equipped, remove ride height sensor connectors.
Support final drive unit from below using transmission jack
(BMW special tools 00
2 030 and 33 4 390 or equivalent).
NOTE-
Special tool 33 4 390 will need modifications to cradle the ii-
nal drive properly.
4 Remove right and left suspension trim panels (arrow)
4 Remove right and left lower strut mount bolts (arrow)
Remove rear suspension
subframe by removing 4 mounting
bolts (arrows).
Carefully lower rear suspension
subframe away from body to
remove.

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Rear Suspension
- Remove exhaust system. See 180 Exhaust System.
- Detach driveshaft from differential. See 260 Driveshaft.
- Remove brake caliper and brake disc. Hang brake caliper
aside with stiff wire. Do not disconnect brake fluid hose. See
340 Brakes.
- Remove left and right ABS sensors from wheel bearing car-
riers.
Disconnect parking brake cable from brake shoe expander.
See 340 Brakes.
Remove heat shield from above driveshaft
If equipped, remove ride height sensor connectors
CAUTION-
Models with air springs: Disable air supply pump by discon-
necting electrical plug before performing any repairs. Pump is
locatedbeneath a coverunder
thespare tire in the floorof the
carqo compartment.
Models with air springs: Loosen compressed air pipes (ar-
rows) at air distribution assembly to release system pres-
sure.
WARNING -
Vehicle will lower when the air pipes are opened. 1
- 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.
4 Support final drive unit from below using transmission jack
(BMW special tools 00 2 030 and 33 4 390 or equivalent).
NOTE-
Special tool 33 4 390 will need modifications to cradle the fi-
nal drive properly
4 Remove right and left suspension trim panels (arrow),

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---
Rear Suspension
ELECTRONIC HEIGHT CONTROL
(EHC) COMPONENT REPLACEMENT
Sport Premium rear suspension is an option on Sport Wagon
models and standard on
1999 and later V-8 Sport Wagons.
This suspension incorporates electronic height control
(EHC)
using air springs.
With vehicle lifted off the ground,
if the rear air springs can be
compressed by hand, either the spring is defective or the sys-
tem is depressurized.
Locate
EHC faults using BMW scan tools DIS or MoDiC. EHC
description and some troubleshooting is covered in 300 Sus-
pension, Steering and Brakes-General.
Air spring replacement is covered earlier in this chapter. See
Air spring, removing and installing.
CAUTION-
Maintain high levels of cleanliness around air line connec-
tions when disassembling and assembling air suspension
components. Even
small dirt particles can cause leakage in
the pressurized system.
Electronic height control
(EHC) components
1. Air spring
2. 1 liter air reservoir
3. EHC control module
4. Air supply distributor
5. Airsupply pump
(under spare tire)
6. Air spring mounting bolt
(at wheel bearing carrier)
7. Rear ride height sensors
(Hall effect)
8. Air supply pump relay

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-- I
I: ... . -. Rear Suspension! -- .- -
Air compressor pump relay, removing and
installing
- Working in cargo compartment, remove spare wheel.
4 Remove air supply pump fasteners (arrows). Turn pump
over.
- Turn relay plug 45" and remove relay.
EHC control module, removing and
installing
The EHC control module is mounted on the right side of the
spare tire
well in the cargo compartment.
- Remove spare tire.
4 Remove electrical components cover (A).
- Release control module wiring harness plug loclting clip (B)
and remove module.
- Installation is reverse of removal.
- After assembly, reset ride height using BMW diagnostic scan
tool DIS.
Air supply unit, removing and installing
CAUTION-
Maintain high levels of cleanliness around air line connec-
tions when disassembling and assembling air suspension
components. Even small dirt particles can cause
leakage in
the pressurized system.
When the airsupply unit is removed for any reason, reset ride
height using BMW scan tools DIS or
MoDiC.
- Remove spare tire.
i~B,!n,,ayPubi.l,c~u.c~"~-A~~ R

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Rear Suspension
4 Remove air line fittings (A) from bottom of air distribution con-
nectors.
Cut off wire ties.
WARNING-
Vehicle will lower when the air pipes are opened.
4 Rotate air line distribution connector (A) 45" in direction of
arrow to remove.
Rotate electrical connector
(B) 45" in direction of arrow to
remove.
Compress wiring connector locking clips
(arrows) and dis-
connect wiring harness.
< Remove air supply unit mounting fasteners (arrows) and re-
move unit.
- Installation is reverse of removal.
When installing air lines always match line colors.
a After assembly, reset ride height using BMW diagnostic
scan tool DIS.

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330-47
Rear suspension/
Ride height sensor, removing and installing
Hall effect sensors for vehicle height detection are mounted
on the
left and right sides of the rear suspension. A coupling
rod mounted between the rear suspension arm and the sen-
sor arm is used to send a varying voltage signal to the
EHC
control module.
Raise car and support safely.
WARNING-
Male sure the car is firmly supported on jaclc stands de-
signed
for the purpose. Place jaclc stands underneath struc-
tural chassis points. Do not place jaclc stands under
sus~ension Darts.
Working underneath rear of car, remove trim panel (arrow)
just ahead of suspension subframe.
Disconnect electrical harness connector from sensor.
4 Remove control rod mounting nut (arrow).Turn control rod to
access sensor mounting fastener.
- Remove sensor mounting fasteners.
- Remove ride height sensor.
- Installation is reverse of removal.
Make sure sensor lever points outward. After assembly, re-
set ride height using BMW diagnostic scan tool DIS.
Tightening torques
Ride
height sensor to bracket 5 Nrn (44 lb-in)
Lever to height sensor
9 Nrn (80 ib-in)