2001 BMW 525i Ele

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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.
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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)

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Final ~rivel
4 Remove staked collar nut and press output shafl out of wheel
hub with special
BMW tool 33 2 111/116/117.
- Remove drive axle.
- Installation is reverse of removal, noting the following:
Use a new collar nut.
a Apply a light coating of oil to contact face of collar nut and
install it loosely.
* Install road wheel and lower car to ground.
- With an assistant applying brakes, tighten drive axle collar
nut to its final torque.
Stake collar nut.
Tightening torques
-
Drive axle collar nut to drive flange M27 300 Nrn (221 ft-lb)
Drive axle to differential flange
* M10x20 rnm black Torx bolt
83 Nrn (61 ft-lb)
M10x20 rnrn silver Torx bolt
100 Nrn (74 ft-lb)
Road wheel to hub 120 Nrn f 10 (89 ft-lbf7)
Drive axle, removing and installing
(Sport Wagon)
4 With an assistant applying brakes, brealc free staked collar
nut (arrow) at center of rear wheel hub. Do not remove com-
pletely.
NOJE-
The drive flange collar nut is tightened to a torque of over 300
Nm (221 ft-lb). Make sure the car is firmly on the ground.
WARNING -
Disable airsupply pump (if applicable) by disconnecting elec-
tricalplug before performing any repairs. Pump is located be-
neath a cover under the spare tire
in the floor of the cargo
compartment.
- Raise rear of car. Remove rear wheel.
WARNING -
Malce sure that the car is firmly supported on jack stands de-
signed for the purpose. Place the jack stands beneath struc-
tural chassis points. Do not place jack stands under
suspension parts.
- Models with rear coil springs: Remove cargo compartment
floor carpet.

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331-16
I Final Drive
Worlting at top of coil spring, press center cap down or pry
upward to remove. If pushed down, remove from inside coil
spring.
4 Worlting from underneath, position BMW special tool 33 2
301
between 2nd and 3rd spring coil from the bottom.
Make sure tool recess faces upward.
Worlting in cargo compartment, guide BMW special tool
33
2 304
from above and thread into special tool 33 2 301.
4 Worlting 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 end lifts off spring seat on wheel
bearing carrier.
- Model with air springs: Loosen compressed air pipes at air
distribution assembly to release system pressure.
WARNING-
The vehicle will lower when tlie airpipes are loosened.
- Remove final drive. See Final drive, removing and install-
ing.

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General ........................... .34 0.2
Special Tools
....................... .34 0.2
E39 brake system
.................... .34 0.4
Electronic braking and stability control
.... .34 0.4
Troubleshooting
..................... .34 0.5
Warnings and cautions
................ .34 0.7
Bleeding Brakes ................... .34 0.8
Brakes, bleeding
..................... .34 0.9
Brake Pads, Calipers and Rotors ... .34 0.1 1
Braking system components .......... .34 0.11
Brake pads,
checking and replacing ..... .34 0.12
Brake rotors, removing and installing
.... .34 0.15
Master Cylinder .................. .34 0.16
Master cylinder, removing and installing
. .34 0.17
Brake Booster .................... .349 0.1
Brake booster check valve
............ .34 0.19
Brake booster, removing and installing
.. .34 0.20
Parking Brake .................... .34 0.22
Parking brake components
............ .34 0.22
Parking
brake, adjusting .............. .34 0.22
Parking bralte shoes, removing
and installing
....................... .34 0.23
Parking
brake cable, replacing ......... .34 0.24
ABS Component Replacement ..... 340-26
Wheel speed sensor. replacing
......... 340-26
ABS impulse wheel
.................. 340-27
DSC lateral acceleration or
rotational rate (yaw) sensor. replacing
... 340-27
DSC steering angle sensor.
removing and installing
............... 340-28
DSC precharge pump.
removing and installing (1998 models)
... 340-29
DSC pressure sensor
(1 999 - 2002 models) ................ 340-30
ABS /traction electronic control
module
(1 997 -1 998 models) .......... 340-31
ABS
/ DSC control module
(1 999
- 2002 models) ................ 340-31
ABS
/ traction control hydraulic unit.
removing and installing
............... 340-31

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E39 brake system
BMW E39 models are equipped with vacuum power-assisted
four-wheel disc brakes with an integral
Antilock Brake System
(ABS). Single-piston calipers act on vented front and rear ro-
tors. A brake pad wear sensor for each axle indicates when
brake pads need replacement. The dual drum-type parking
brake system is integrated with the rear brake rotors.
Electronic braking and stability control
E39 models were introduced with Automatic Stability Control,
a computer controlled traction control system that uses the
AB5 system in conjunction with engine management controls
to control wheel spin during take-off and maintain vehicle sta-
bility while braking.
Added in the
1998 model year was Dynamic Stability Control
(DSC). This system implements wheel speed modulation
throughout all stages of driving. For example, DSC is able to
reduce understeer by applying differing amounts of braking
force to each wheel, or it can override the engine manage-
ment system during hard cornering.
A summary of distinguishing characteristics of the various
systems is shown in the table
E39 electronic braking and
stability control systems.
For ABS, ASC and DSC system and component descriptions,
see
300 Suspension, Steering and Brakes-General.
WARNING-
A car with electronic stability control is still subject to normal
physical laws. Avoid excessive speeds for the road conditions
encountered.
E39 electronic braking and stability control systems
Year (model)
manuf. up to 911998
(528i, 540i)
manuf. from 911999
(540i optional)*
From
911 999
(ail models) System
Automatic Stability Control (ASC) Identifiers
Electronic control module next to glove compartment
Hydraulic unit in right rear of engine compartment
No precharge pump
Dynamic Stability Control
(Bosch DSC
Ill v. 5.3)
Dynamic
Stabil~ty Control
(Bosch DSC
Ill v. 5.7) Electronic
control module next to glove compartment
Hydraulic unit in right rear of engine compartment
Precharge pump in left front of engine compartment, below steering
fluid reservoir
Separate rotational rate (yaw) and lateral acceleration sensors
Control
modulelhydraulic unit in right rear of engine compartment
No precharge pump
Combined rotational rate (yaw) and lateral acceleration sensors

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Brakes
Troubleshooting
Brake performance is mainly affected by three things:
Q Level and condition of brake fluid
Ability of bralte system to create and maintain pressure
Condition of friction components
Air in bralte fluid will
make the brake pedal feel spongy during
braking
orwill increase the bralte pedal force required to stop.
Fluid contaminated by moisture or dirt can corrode the sys-
tem. lnspect the brake fluid inside the reservoir. If it is dirty or
murky, or is more then two years old, replace fluid.
To
check the function of the master cylinder hold the bralte
pedal down hard with the engine running. If the pedal slowly
falls to the floor, either the master cylinder is leaking internal-
ly, or fluid is leaking externally.
lnspect the rotors for glazing, discoloration and scoring.
Steering wheel vibration while braking at speed is often
caused by warped rotors, but can also be caused by worn
suspension components.
When troubleshooting, keep in mind that tire inflation, wear
and temperature can all have an affect on braking. See
300
Suspension, Steering and Brakes-General for additional
suspension and brake system troubleshooting.
The table Brake system troubleshooting lists symptoms of
brake problems, probable causes, and suggested corrective
actions. Unless noted otherwise, relevant repairs are de-
scribed later in this repair group.