Air suspension BMW X5 2001 E53 Workshop Manual

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Introduction
The X5 marks BMW’s introduction into the luxury “Sports Activity Vehicle (SAV)” niche seg-
ment of the Sport Utility Vehicle market. While carrying the designation X5, the vehicle is not
based on the 5 Series but it is its own new car-like platform. The X5 is offered with two
engine variants:
• The 4.4 liter M62 TU engine equipped with the A5S 440 Z automatic transmission.
• The 3 liter M54 engine with either the GM 5 automatic or 5 speed manual transmission
The X5 incorporates the following
features:
• Four wheel independent sus-
pension (BMW tradition)
• Full time - all wheel drive
(planetary gear transfer case)
• All road vehicle (ON/OFF road
capabilities)
• High ground clearance
• Unitized body and Chassis
(car like ride and handling)
• Double pivot front suspension
• “Integral Link” rear suspen-
sion with air spring self level-
ing
• X5 specific traction control
system
Two different suspension options are offered (standard and sport) with different springs,
shock absorbers and stabilizers.
The X5 has 180 mm ground clearance, for both suspensions to allow off road travel.
However, the suspension travel is the same as the E39 which allows the X5 to retain a car
like feel when driven every day.
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Front Suspension
The front suspension design is taken from the E38/E39 double pivot system. The compo-
nents are larger in size and made from all steel for the expected harder use that the X5 sus-
pension will receive. This includes the sub-frame which is also larger in size and supported
by two hydraulic mounts for vibration absorbion. The front suspension carrier incorporates
an aluminum stiffening plate that is bolted to the carrier. It adds to the front axle kinematics
by reducing flex in the front suspension. It also provides protection for the oil pan and front
end components when off-road and improves the Cd by providing a smooth surface for air
flow under the vehicle.
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Front Axle Technical Data
TRACK: 1576mm
TOE-IN: 18’ +/-10’
CAMBER: -12’ +/- 20’
S.A.I: 12 Degree’s 48 Feet
CASTER: 7 Degree’s 8 Feet

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Rear Suspension
The rear suspension is the “intragal” multi-link design taken from the E38/E39 vehicles.
Several components AER made from aluminum to erduce the unsprung weight. The X5
with the M62TU engine uses the EHC (air spring) suspension system. The EHC functions
the same as the E39 Sport Wagon with only minor differences to the components and lay-
out of the system. The X5 with the M54 engine will use standard springs in the rear with the
EHC system as an option. The rear struts on the X5 are mounted to the body instead of
the sub-frame.
The rear axle sub-frame is mounted to the body through four bushings (larger than E38) for
increased load and comfort. The rear differential is mounted through three rubber bushings
two in the front and one hydromount in the rear. The wheel bearings are similar to the E39
but incorporate different seals - designed for off-road use.
New special tools are available for adjusting the rear suspension due to the limited space.
Rear Axle Technical Data
Track: 1576mm
Toe In: 18 Feet
Camber 1 Degree 50 Feet

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Overview of EHC Control System
The control philosophy of EHC is to "Initiate a control sequence only when necessary". The
system offers the following advantages:
• The control system operates independently from the vehicle’s engine (no engine driven
hydraulic pump system as per previous self leveling systems).
• Individual control of the rear wheels is possible
• An uneven load is identified and compensated for
• Uneven road surfaces are identified and not compensated for
• Automatic control is interrupted when cornering
• The system is diagnosable using the DIS or MoDiC
The air suspension system consists of the following components:
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Air Springs
The air spring is made from a flexible rubber material. It
forms an air tight cavity which provides the calculated spring
rate required for the sport wagon.
As the spring compresses downward the bottom edge of
the rubber material rolls along the vertical surface of the
base mount cylinder.
Air is added or removed from the air spring through its top
port. The top port of each spring is connected to a reser-
voir and the air supply pipes. The reservoirs are required to
hold additional air due to the compact design of the springs.
Rear Axle Level Sensors
Hall effect sensors are mounted on the left
and right sides of the rear suspension for ride
height detection. They are pivoted by a cou-
pling rod through the rear axle swing arms.
The hall sensors produce a varying voltage
input to the control module as the suspension
height changes.
If the vehicle is equipped with Xenon head-
lights the right side sensor contains an addi-
tional sensor for the automatic headlight level
adjustment system.
Warning Display
If the system is faulted and off-line or set in the transport mode, the following is displayed:
High Cluster: A message is posted in the high cluster matrix display.
E39 Features 07
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