brake rotor BMW 325xi SEDAN 2003 E46 Owner's Manual

114Special operating instructions
Break-in proceduresTo ensure that your vehicle continues to
provide maximum economy throughout
an extended service life, we request
that you devote careful attention to the
following instructions.Engine and differentialThe first 1,250 miles/2,000 km:
Attempt to constantly vary both vehicle
and engine speeds during these initial
miles while remembering to avoid
engine speeds in excess of 4,500 rpm
and/or vehicle speeds of over
100 mph / 160 km/h:
Always obey all official speed limits.
Refrain from using full throttle and avoid
pressing the accelerator beyond the
kickdown point.
You can then proceed to increase both
engine and vehicle speeds once the ini-
tial 1,250 miles/2,000 km have elapsed.
Please remember to observe these
same break-in procedures if either the
engine or the differential should have to
be replaced later in the course of the
vehicle's service life.
TiresOwing to technical factors associated
with their manufacture, tires do not
achieve their full traction potential until
an initial break-in period has elapsed.
We thus ask you to drive with extra care
during the first 200 miles/300 km.
Always obey all official speed limits.
When the vehicle is operated on
wet or slushy roads, a wedge of
water may form between the tire and
the road surface. This phenomenon is
referred to as hydroplaning and can
lead to partial or complete loss of trac-
tion, vehicle control and braking effec-
tiveness. Reduce your speed on wet
roads. before the brake pads and rotors
achieve the optimal pad-surface and
wear patterns required for trouble-free
operation and an extended service life
later on.
To break in the separate parking brake
drums, apply the parking brake lightly
when coasting to a standstill – at a traf-
fic signal, for instance; use caution to
avoid posing a danger to other road
users.
You can prevent corrosion in the drums
by periodically repeating this proce-
dure.
The brake lamps do not come on
when the parking brake is set.
Vacuum for the brake system servo unit
on your BMW is available only when the
engine is running. When you move the
vehicle with the engine off – when tow-
ing, for example – substantially higher
levels of pedal force will be required to
brake the vehicle. before the clutch starts to operate at
optimum efficiency. Remember to
engage the clutch carefully during this
initial period.

116
Brake systemBrake fluid levelIf the brake fluid level is too low and
brake pedal travel has become longer,
there may be a defect in one of the
brake system's hydraulic circuits.
Proceed to the nearest BMW cen-
ter. It may be necessary to apply
higher levels of pressure to the pedal
when stopping and braking distances
may also be longer. Please remember
to adapt your driving style accord-
ingly. with the vehicle parked or in storage,
and operating conditions in which brak-
ing is restricted to gentle, low-pressure
applications will all increase the ten-
dency for corrosion to form on the
rotors; this is often accompanied by a
simultaneous accumulation of contami-
nation on the brake pads. The pads
must exert a certain minimal level of
pressure against the rotors for the disc
brakes' inherent self-cleaning effect to
remain effective; the pressure available
under the above conditions may not
provide adequate cleansing.
If the brake rotors are corroded, they
will tend to respond to braking with a
pulsating effect that even extended
brake applications will fail to cure.
When driving in heavy rain and on wet
roads it is a good idea to apply light
pressure to the brake pedal every few
miles. Monitor traffic conditions to
ensure that this maneuver does not
pose a hazard to you or to other road
users. The heat generated in this pro-
cess helps dry the pads and rotors to
ensure that your brake system will
respond with undiminished efficiency
when you need it.
When descending steep hills and
extended grades, downshift to a gear
that will allow you to continue safely
with only a minimal amount of braking.
By minimizing the loads placed on the
brake system, this strategy helps
ensure that optimal brake system
response will remain available at all
times. Use care to avoid exceeding the
approved engine-speed range, refer to
page 71.
Do not coast with the clutch
depressed or with the transmis-
sion or selector lever in Neutral. Do not
coast with the engine shut off. The
engine provides no braking effect when
the clutch is depressed and there is no
power-assist for braking or steering
when the engine is not running.
BMW 325xi, 330xi: always refer all
brake inspection and service work to
your BMW center, as failure to observe
the special procedures could result in
damage to components of the all-wheel
drive.
Never allow floor mats, carpets or any
other objects to protrude into the area
around the accelerator, clutch and
brake pedals and obstruct their move-
ment. For your own safety: use only
brake pads that BMW has
released for your particular vehicle
model. BMW cannot evaluate non-
approved brake pads to determine if
they are suitable for use, and therefore
cannot ensure the operating safety of
the vehicle if they are installed.<