Get Operation, care and maintenance -> Brakes: ABS, DBC, Disc brakes Guide for BMW Z8 Roadster First Generation (2000-2003)

⁸⁸ⁿAntilock Brake System (ABS)

On road surfaces that have a loose

surface layer on a firm base with good

traction (on gravel, deep sand or snow,

for example), braking distances may be

longer than with locked wheels. This

also applies to driving with snow

chains. However, ABS continues to

provide enhanced vehicle stability and

steering response under these condi-

tions.

The concept

Braking with ABS

ABS enhances active safety by helping The system is operative once the

to prevent the wheels from locking

under braking. Why is this important?

When front wheels lock up and cease

to turn, the tires break into a slide.

Result: the driver loses the ability to

steer the vehicle. Traction loss at the

vehicle exceeds a speed of approx.

6 mph (10 km/h). The ABS is deacti-

vated whenver the vehicle's speed

drops back below approx. 4 mph

(6 km/h). This means that the wheels

can lock only in the final phase of a

rear wheels can cause the back end of panic stop – a factor of no substantive

significance in actual use.

the vehicle to slip sideways and break

away in uncontrolled oversteer.

The ABS system works best in situa-

With ABS, you will achieve the shortest- tions requiring maximum pressure on

possible braking distances under all

given conditions (braking while driving

straight ahead or in curves, different

road surfaces).

the pedal (full braking). Since the

vehicle maintains steering responsive-

ness, you can nevertheless avoid

possible obstacles with a minimum of

steering effort.

ABS is designed to meet two essential

requirements during every brake appli- The ABS system's closed-loop control

cation:

circuit cycles in fractions of a second.

A pulsing of the brake pedal, combined

with the sounds associated with the

hydraulic controls, tells you that the

brake system is within its maximum

limit range and reminds you that you

should adapt your vehicle's speed to

road conditions.

> To help provide vehicle stability

> To help retain steering and maneu-

vering capability on all types of road

surfaces (asphalt, concrete, dirt, wet

surfaces, snow and ice).

Antilock Brake System (ABS)

89n

Information for your safety

In case of a system malfunction

Not even ABS can suspend the laws of

physics. The consequences of brake

applications with inadequate clear-

ances for safety between vehicles,

excessive speed or if aquaplaning

occurs are always the responsibility of

the driver. You should never allow the

added safety provided by ABS to

mislead you into taking risks of any

kind.

If the ABS warning lamp comes

on, refer to page 21. The brake

system will then function the

same as on vehicles without

ABS. However, have the brake

system checked by your BMW

center as soon as possible. To prevent

undetected defects and cumulative

faults from adversely affecting the

brake system, refer any problems to

your BMW center at the earliest oppor-

Do not make any modifications to tunity.

the ABS system.

Service procedures on ABS are to be

performed by authorized technicians

only.<

Cornering Brake Control (CBC)

CBC is an advanced ABS engineering

design. Vehicle stability is also

enhanced when braking during

cornering at high rates of lateral accel-

eration and during lane changes.

⁹⁰ⁿDynamic Brake Control (DBC)

Disc brakes

If you step on the brake rapidly, this

system automatically produces maxi-

mum braking force boost and thus

helps to achieve the shortest-possible

braking distance during "panic stops."

All of the benfits of the ABS system are

exploited under these circumstances.

Disc brakes furnish optimal decelera-

tion and braking control and greater

fade resistance under heavy use.

For your safety

Not even DBC can suspend the laws of

physics. The consequences of brake

applications with inadequate clear-

ances for safety between vehicles,

excessive speed or if aquaplaning

occurs are always the responsibility of

the driver. You should never allow the

added safety provided by DBC to

When the vehicle is driven only occa-

sionally, during extended periods when

the vehicle is not used at all, or in oper-

ating conditions where brake applica-

tions are less frequent, there is an

increased tendency for corrosion of the

rotors and accumulation of contamina-

tion on the brake pads. This occurs

because the minimal pressure which

must be exerted by the pads to clean

the disc brakes by brake applications is

not achieved.

Do not reduce the pressure on the

brake pedal during the brake applica-

tion. When the brake pedal is released, mislead you into taking risks of any

the DBC is deactivated. kind.

In the event of a malfunction,

the yellow brake warning lamp

comes on. Normal braking effi-

ciency and ABS are still fully

available. Have the system

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.

checked and repaired at your

BMW center as soon as possible.

For your own safety: use only

brake pads BMW has approved

for your specific vehicle model. BMW

cannot evaluate non-approved brake

pads to determine if they are suited for

use, and therefore cannot ensure the

operating safety of the vehicle if they

are installed.<

Disc brakes

91n

Even if engine braking fails to slow the

vehicle sufficiently, you should still

make every effort to avoid prolonged

braking with continuous application of

low to moderate pressure at the pedal.

It is better to decelerate the vehicle by

applying a higher level of force at the

pedal (watch following traffic!) and then

subsequently pausing to allow the

brakes to cool briefly before starting on

your next braking cycle. By protecting

brake system components against

overheating, the cooling phases

Driving notes

When driving in heavy rain and on wet

roads it is advisable to apply light pres-

sure 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 braking process helps

dry the pads and rotors

Maximum braking force is obtained

while the wheels are not locked, but

rather when they are still barely turning

immediately prior to locking. ABS main-

tains this state automatically. If the ABS

fails, you should revert to the staggered

braking technique (refer to page 93).

afforded by this staggered, or intermit-

tent braking technique help maintain

consistent availability of optimal braking

response when it is needed.

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.

Do not coast with the clutch pedal

depressed, the gear-shift lever in

neutral, or, above all, with the engine

off; otherwise, the engine will provide

no braking effect if the transmission is

in neutral, and there is no braking or

steering power assist if the engine is

not running. Never allow floor mats,

carpets or any other objects to obstruct

the accelerator, clutch or brake pedals

and pose a safety hazard by reducing

their available travel range.<

You can enhance the engine's braking

effect by downshifting, into first gear, if

necessary.

⁹²ⁿBrake system

Winter operation

Winter is often accompanied by rapid

changes in weather, requiring not only a

different driving style, but also certain

preparations to the vehicle itself to

ensure that your progress through the

winter months remains safe and

trouble-free.

Brake fluid level

Brake pads

The brake warning lamp comes

on with the parking brake

released:

The warning lamp for the brake

pads comes on:

The brake pads have reached

their minimum thickness. Proceed to

the nearest BMW center as soon as

possible to have the pads replaced.

The brake fluid level in the

reservoir is too low, refer to

page 114.

If the brake fluid level is too low and

brake pedal travel has become notice-

ably longer, there may be a defect in

one of the brake system's hydraulic

circuits.

Coolant

For your own safety: use only

brake pads which BMW has

Be sure that the coolant mixture

contains the year-round ratio of 50:50

water and extended-duty antifreeze

with corrosion inhibitor. This mixture

provides protection against freezing

down to approx. –34 7 (–37 6).

approved for your specific vehicle

model. BMW cannot evaluate non-

approved brake pads to determine if

they are suited for use, and therefore

cannot ensure the operating safety of

the vehicle if they are installed.<

Proceed to the nearest BMW

center. Higher brake application

pressure may be necessary under these

conditions, and brake pedal travel may

be significantly longer. Please

remember to adapt your driving style

accordingly.<

Locks

BMW door lock deicer can be used to

free doors if frozen. This deicer also

contains lubricant.

After using the deicer, treatment with

BMW lock cylinder grease is recom-

mended.

Operation, care and maintenance -> Brakes: ABS, DBC, Disc brakes for Your BMW Z8 Roadster First Generation (2000-2003)

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