engine BMW 525i 1998 E39 Workshop Manual

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330-5
Rear Suspension
REAR STRUTS AND SPRINGS
(SEDAN MODELS)
Rear strut assembly, removing and
installing
Replace struts and coil springs in pairs only.
- Raise car and remove rear wheels.
WARNING -
Male 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 rear parcel shelf:
Remove rear seat headrests by pulling straight up.
Remove both rear roof pillar (C-pillar) trim panels.
Unbolt rear seat
belt anchors. See 720 Seat Belts.
Models with fixed rear seat: Remove rear seat backrest.
See 520 Seats.
* Models with fold-down rear seat: Remove rear seat back-
rest side sections. See 520 Seats. Fold down backrest.
* Working inside trunk, remove roller blind mounting nuts
and bolts, if applicable. Also disconnect roller blind har-
ness connector at right edge of rear seat backrest.
Gently pry rear speaker cover grilles and rear window defog-
ger grilles
(A) out of parcel shelf.
Carefully remove seat belt and headrest mount finisher
strips (B).
Remove
middle seat headrest anchor bolts (C). Remove
headrest anchor.
Remove expansion rivets (arrows) and lift out parcel shelf.
- Remove rear speakers.
- Remove rear wheels. Remove wheel arch trim
- Support rear wheel bearing carrier.
CAUTION-
The strutassembly prevents the drive axle and wheel bearing
carrier
from dropping too far. Supporting the wheel bearing
carrierbefore disconnecting the strut mounting fasteners pre-
vents damage to the brake hose, parking brake cable and
drive axle
CV joints.

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330-6
Rear Suspension
4 Remove rear strut top cover. Remove upper strut mounting
nuts (arrows).
Remove strut assembly lower mounting bolt (arrow).
Disassemble strut and spring assembly as described below
in Rear strut assembly, disassembling and reassem-
bling.
Installation of assembly to car is reverse of removal, noting
the following:
Make sure all threaded bolts, nuts and mating surfaces are
clean.
Install strut assembly top mount using new self-loclting
nuts.
Malte sure long lower strut bushing fits in
hole in wheel
bearing carrier.
Tightening torques Strut to wheel bearing carrier 127 Nm (94
it-lb)
Strut mount to body
Gray fasteners 28 Nm (21 ft-lb)
Yellow fasteners 24 Nm
( 18 it-lb) -
Road wheel to hub 120ilO Nm (89i7ft-lb)

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Rear ~us~ensionl
Rear strut assembly, disassembling and
assembling
Replace struts and coil springs in pairs only
Replacing the upper strut mount, spring or strut requires that
the strut assembly first be removed from the car, as described
earlier. Strut disassembly requires a spring compressor.
WARNING-
Do not attempt to disassemble the strut without a spring com-
pressor designed specifically for the job.
- Remove strut assembly from car as described in Rear strut
assembly, removing
bnd installing
4 Mount spring compressor (BMW special tools 31 3 340 and
31 3 350 or equivalent) in shop vice. Install correct-sized
spring retainers
(A).
WARNING-
Do not attempt to disassemble the struts without a spring
compressor designed specifically for this job.
* Prior to using the spring compressor checlc its opera-
tion. Do not use a spring compressor that is damaged.
Do not make any modifications to the spring compres-
sor.
Never use an impact wrench to compress or relieve
tension when using a spring compressor.
1
- Place strut assembly coil spring in spring retainers. Com-
press spring until force on upper strut mount is relieved.
Remove strut top mount self-locking nut with BMW special
tool
31 2 21 0 while counterholding strut shaft with a box end
wrench.
- Remove upper strut mount and related components. Sepa-
rate strut from spring.
NOTE-
Store the removed shock absorber upright Do not allow it to
lie horizontally or upside down for any length of time. If incor-
rect storage has occurred, place the
shoclc absorber upright
with the rod
fully extended for at least 24 hours.
- Replace strut, rubber bumper, upper strut mount or spring,
as needed.
NOTE- Relieve tension on spring compressor slowly and carefully.
Fit new spring in spring compressor so that one coil at
each end is outside spring retainer.

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330-8
Rear Suspension
4 Compress spring and install it and related components to
shock absorber. Use new self-locking upper strut mounting
nut.
1. Upper strut mount self-locking nut
2. Washer
3. Poor road surface adapter
4. Upper spring seat
5. Upper strut mount
6. Upper rubber bumper seat
7. Rubber bumper
8. Coil spring
9. Dust boot
10. Lower spring seat
I I. Strut
WARNING-
Male sure the upperself-locking nut is fully tightened before
releasing the spring compressor.
Tightening torque
Upper strut mount to strut shaft
27 Nm (20 ft-lb)
(M14, replace self-locking nut)
4 Before releasing spring tension, position upper strut mount
so that one threaded stud is on a plane with flat end of strut
bushing at other end of strut.
- Release spring compressorslowly, positioning spring ends in
shoulders of spring seats.
- Reinstall strut assembly in vehicle, as described above in
Rear strut assembly, removing and installing.

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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 0
/Rear Suspension
- Remove rubber protective cap from shock absorber upper
mount.
- Remove shock absorber upper mounting nuts.
- Remove shock absorber lower mounting bolt. Lower shock
absorber out of wheel housing.
< Transfer shock top mounting plate, dust cover (if applicable)
and related components to new shoclc absorber.
1. Self-locking nut
2. Washer
3. Upper siioclc absorber mount
4. Rubber bumper seat
5. Rubber bumper
6. Dust boot
7. Shock absorber
8. Long lower bushing
Tightening torques
Shock absorber to upper mount
27 Nm (20 it-lb)
(M14, replace self-locking nut)
- Installation on car is reverse of removal, noting the following:
Make sure all threaded bolts, nuts and mating surfaces are
clean.
Install shock absorber upper mount to
subframe using new
self-locking nuts.
. Make sure long lower shock absorber bushing fits in hole
in suspension swing arm.
Tighten lower shoclc absorber bolt to its final torque once
car is on ground.
Tightening torques
Quick coupling screw to air 2 Nm (18 in-lb)
shock absorber
Road wheel to
hub 120 &I0 Nm (89 -f7 ft-lb)
Shock absorber to swing arm 127 Nm (94 ft-lb)
Strut mount to body
Gray fasteners
Yellow fasteners
24 Nm ( 18 it-lb)

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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.

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330-1 3
Rear Suspension
1 1 4 Check roll fold of air spring (arrows). Reinstall only if roll fold
is undamaged and formed correctly.
- To install air spring:
Check sealing O-rings at air spring inlet. Replace
if dam-
aged. Do not grease O-rings. Reinstall protective plug.
* Install spring above suspension subframe. Make sure ec-
centric lug at bottom of air spring fits in recess of
subframe
spring seat.
Reattach top spring mounting clips.
- Reattach air line connections.
- Remainder of installation is reverse of removal.
Tightening torques
Air line connection
2 Nm (1 8 in-lb)
Air spring
to wheel bearing carrier 20 Nm (1 5 ft-lb)
Road
wheel to hub 120 510 Nm (89-F-7 ft-lb)
REAR SUSPENSION ARMS,
SUBFRAME AND BUSHINGS
A damaged suspension arm orworn bushings will change the
rear wheel alignment and may adversely affect handling and
stability.
WARNING-
Do not attempt to straighten a damaged suspension arm.
Bending or heating may
weaken the original part. Always re-
olace a damaoed susoension arm.
Rear suspension arm
components
1. Eccentric washer
(for rear toe adjustment)
2. Upper front control arm
(guide link or traction strut)
3. Outer swing arm bushing and
integral link
4. Swing arm (lower control arm)
5. Upper rear control arm
(wishbone)
6. Wheel bearing carrier
7. Circlip
8. Swing arm ball joint
9. Eccentric washer
(rear camber adjustment)

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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.