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020-24
Maintenance
tions. In general, replacement batteries should always be
rated equal or higher than the original battery.
The battery is held in place by a single hand screw and plate.
A secure battery hold-down is important in order to prevent
vibrations and road shoclt from damaging the battery.
CAUTION-
Prior to disconnecting the baitem read the battery discon-
nection cautions given in
001 General Cautions and
Warnings.
NOTE-
Always disconnect the negative (-) cable first, and connect
it last. While changing the battery, clean away any corro-
sion in or around the battery tray
More battery and charging system information is in 121
Battery, Alternator, Starter.
Brake fluid, replacing
Brake fluid absorbs moisture easily, and moisture in the fluid
affects bralte performance and reliability. This is why
BMW
strictly recommends replacing the bralte fluid every two
years. When replacing or adding bralte fluid, use only new
fluid from previously unopened containers. Do not use brake
fluid that has been bled from the system, even
if it is brand
new. Use only DOT
4 brake fluid.
NOTE-
See 340 Brakes for brake fluid flushing procedures.
Brake pad 1 rotor wear, checking
Disc brakes are fitted at all four wheels. Although the brakes
are equipped with a brake pad warning system, the system
only monitors one wheel per axle. Pad thickness should be
checked whenever wheels are off or brake
worlt is being
done.
4 Disc brake pad wear can be checked through opening in
caliper:
Measure distance
(A) of brake pad "eai' to bralte rotor.
See
340 Brakes. Compare to specification below.
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Driveshaft
4 Driveshaft center slide nut spanner
(Tool No. BMW
26 1 040)
7, 25 1 Ho 4 cv joint removal tool
(Tool No. BMW 26 1 11 0)
support assembly
Driveshaft description
4 The two-piece driveshaft is connected to the transmission by
a rubber flex-disc and to the rear final drive by a constant ve-
locity (CV) joint.
A universal joint is used at the center of the driveshaft and
the shaft is supported in the middle by a center support
bearing. The bearing is mounted in rubber to isolate vibra-
tion.
- The rear constant velocity joint compensates for fore and
aft movement of the drive line.
Troubleshooting
The source of driveline vibrations and noise can be difficultto pin-
point. Engine, transmission, rear axle, or wheel vibrations can be
transmitted through thedriveshaftto the car body. Noises from
thecar may be caused by final drive problems, or by faulty wheel
bearings, drive axles, or even
wom or improperly inflated tires.
NOTE-
For drive axle repair information, see 331 Final Drive
Driveshaft noise or vibration may be caused by worn
ordam-
aged components. Check the universal joint for play. With the
driveshaft installed, pull and twist the driveshaft while watch-
ing the joint. The
BMW specification for play is very small, so
almost any noticeable play could indicate a problem.
Check the torque of the fasteners at the flange connections.
Check the rubber of the flex-disc and center bearing for dete-
rioration or tearing. Check the driveshaft for broken or miss-
ing balance weights. The weights are welded tabs on the
driveshaft tubes. In addition to inspecting for faulty driveshaft
parts, the installed angles of the driveshaft should also be
considered.
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1 Driveshaft
Further inspection requires removal of the driveshaft. Checlc
the front centering guide on the transmission output flange for
damage or
misalignment. Also check runout at the transmis-
sion output fiange and output shaft, and at the final drive input
fiange. Check the bolt hole bores in the flange for wear and
elongation.
Driveshaft flange
runout (max. allowable)
Transmission
flange
- Axial play 0.10 mm (0.004 in.)
Radial play 0.07
mm (0.003 in.)
Spin the driveshaft center bearing and
check ior smooth op-
eration without play. Check the constant velocity joint
forwear
or play. Checlc the universal joint for wear or binding. If it is
difficult to move or binds, the driveshaft section should be
replaced.
Universal joint
play
Maximum allowable 0.15
mm (0.006 in.)
NOTE-
With the driveshaft installed, the actual amount that the drive-
shaftjoint pivots is limited. For the most accurate test, check
joint
in its normal range of movement.
If inspection reveals nothing wrong with the driveshaft, it may
need to be rebalanced. This can be done by a speciality drive-
shaft repair shop. Also,
checlc driveshaft alignment as de-
scribed below.
NOTE-
Minor driveshaft vibrations can often be corrected simply by
disconnecting the driveshaft at the final drive and reposition-
ing it go", 180" or 270" in relation to the final drive input
flange.
The troubleshooting table below lists symptoms
oi driveshaft
problems and their probable causes. Most of the repair infor-
mation is contained within this repair group. There are refer-
ences to other repair groups, where applicable.
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Body shell
Exterior and aerodynamics
Crash behavlor -frontal impact
-side impact
Body
-rear impact Structural body components -rigidity
-rollover -strength -vibrations -acoustics
Bumpers compartment lid -bendable Seets,.steerlng system .dents -vibrations bars -vibration patterns
Fenders -aerodvnamic
With its traditional styling features, such as the ltidney grille.
circular headlights behind a glass cover (for reasons of
streamlining), and the
"kiclt" in the rear most roof pillar (C-pil-
lar), the E39 can be immediately recognized as a BMW.
The BMW 5 Series chassis is a unibody design constructed of
high strength steel. Attaching parts, such as the front fenders,
rear quarter panels, doors,
trunk lid and hood are also con-
structed of
steel.
Computer aided design (CAD) techniques have been used in
refining the
E39 body to reduce vehicle weight while retaining
strength and increasing torsional rigidity. For good handling
purposes, the more rigid the structure the more precisely the
suspension can operate.
Wind resistance
Windows bonded flush to the body and the guided flow of
cooling air into the engine compartment provide the
carwith a
good coefficient of drag (Cd).
E39 cars have been designed
for balanced aerodynamics but not necessarily an extremely
low Cd. See table below.
Windshield wipers are designed for effectiveness at speeds
up to and beyond 200
ltph (124 mph).
Coefficient of aerodynamic drag (Cd)
6-cylinder sedan 0.30
V-8 sedan 0.31
6-cylinder Sport Wagon 0.31
V-8 Sport Wagon 0.33
Fenders
The exterior panels are corrosion-resistant zinc coated (gal-
vanized) steel. The front fenders are bolted on. For front fend-
er replacement information, see
410 Fenders, Engine
Hood.