Maintenance Program - BMW 1989-1995 525i Service Manual

020-16
MAINTENANCE PROGRAM
NOTE-
Special sockets for replacing the oxygen sens or are
availabfe from most automotive pans stores. The sock-
et has
a
groove cut down one side to allow the sensor
to be installed without damaging the wire harness. See
010 Fundamentals l or the Do-It-you rse lf Owner
for
information on sources.
UNDER-CAR MAINTENANCE
Tires, checking inflation pressure
Correct tire inflation pressures are important to handling
and stability. fuel economy. and tire wear. Tire pressures
change with temperature. Pressures should be checked often
during seasonal temperature changes. Correct inflation pres-
sures can be found on the driver's door pillar and in the own-
er's manual. Note that tire pressures should be higher when
the car is more heavily loaded.
WARNING-
Do not inflate any tire to
a
higher pressure than the
tire 's maximum inflation pressure listed on the side-
wall. Use care when adding air to warm tires. Warm
tire pressures can increase as much as 4 psi (0.3
bar) over their cold pressures.
Tires, rotati ng
BMW does not recommen d tire rotation. Owing to the car's
suspension design. the front tires begin to wear first at the out-
er shoulder and the rear tires begin to wear first at the middle
of the tread or inner shoulder. Rotating the tires may adverse-
ly affect road handling and tire grip.
NOTE-
The main purpose of tire rotation is to pro mote even
wear and maximum tire life. Tire life may be decreased
slightly If the tires are not rotated.
Wheels, aligning
BMW recommends checking the front and rear alignment
once a year and whenever new tires are installed. See 320
Steering an d wheel ali gnment for a more detailed discus-
sion of alignment requirements and specifications.
Brake system, inspecting
Routine maintenance of the brake system includes main-
taining an adequate level of brake fluid in the reservo ir. check -
ing brake pads for wear. checking hand brake function. and
inspecting the system for fluid leaks or other damage.
UNDER-CAR MAINTENANCE
WARNING-
• Friction materials such as brake linings may con-
tain asbestos fibers. Do not create dust by grind-
ing. sanding. or cleaning the pads with
compressed air. Avoid breathing asbestos fibers
and asbestos dust.
as
it may resul t in serious dis-
eases such as asbestosis and cancer. or in
death.
• Brake fluid is poisonous. Do not siphon brake lIu-
id by mouth. Wear gloves when working with
brake fluid or brake pads to prevent contamina ·
tion of cuts.
Brake hoses and li nes, inspecting
Check that all brake hoses are correctly routed to avoid
chafing or kinking. Inspect unions and brake calip ers for signs
of fluid leaks. Inspect rigid lines for corrosion. dents. or other
damage. Inspect flexible hoses for cracking . Replace faulty
hoses or lines as described in 340 Brakes .
WA RNING -
Incorrect installation or overtightening hoses. lines.
and unions may cause chafing or leakage. This can
lead to partial or complete brake system failure.
Brake pad/rotor wear, checking
Although the cars covered by this manual are equipped with
a brake pad warning system. the system only mon itors one
wheel per axle. There can be slight variations in brake pad
wear at each wheel . so brake pad thickness should be
checked whenever the wheels are off or brake wo rk is being
done.
The brake caliper should be removed to properly inspect
the brake pads and the rotors. Brake caliper rem oval and in-
stallation procedures are given in 340 Brake s. See Fig. 18.
Brake Pad Lining Min imum Thickness
(Dimensi on A)
• Front and rear disc brake pads 2.0 mm (0.08 in)
NOTE-
For parking brake lining wear. see Parking Brake.
checking below.