BMW F97, Техническое учебное пособие

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F97/F98�Complete�Vehicle
5.�Chassis�and�Suspension
53
The�diameter�of�the�rear�perforated�M�compound�brake�disc�is�25 mm�larger�than�that�of�the�G01/G02
BMW�M40i.�Apart�from�the�blue�paint�finish,�the�rear�brake�caliper�including�the�electromechanical
parking�brake�has�been�carried�over�from�the�standard�production�models�and�is�a�single-piston
floating�caliper.
The�characteristic�maps�of�the�M�Dynamic�Stability�Control�have�been�adapted�specifically�to�the
M�design.
M�carbon�ceramic�brakes
M�carbon�ceramics�brakes�are�not�offered.
Brake�noise
• Humming�of�the�BMW�M�compound�brake�disc�at�high�speeds
• Squeaking�brakes�shortly�before�coming�to�a�halt
• Cracking�noises�from�the�area�of�the�BMW�M�compound�brake�discs�when�hot.
Explain�to�the�customer�at�this�point�that�such�noises�occurring�temporarily�or�in�specific�situations�are
inherent�in�the�design�and�do�not�represent�a�quality�problem.�They�are�a�consequence�of�the�special
performance�of�the�brakes�and�do�not�pose�any�danger�or�risk�of�damage.
Point�out�that�the�customer�can�use�his/her�braking�technique�to�help�prevent�the�noises�occurring�or
ensure�they�quickly�disappear�again.�For�example,�after�washing�the�vehicle�it�is�important�to�dry�the
brakes�out�by�braking�(braking�a�few�times�from�50 km/h�(31�mph)�to�0�is�sufficient).�Or�that�the�brakes
can�have�a�tendency�to�squeak�if�they�go�through�long�periods�when�they�are�only�exposed�to�light
braking,�which�is�why�braking�hard�a�few�times�can�help�out�(=�higher�brake�temperature).�After�driving
the�vehicle�very�hard�and�subjecting�the�braking�system�to�high�loads�(high�brake�disc�temperatures)
the�driver�should�try�to�make�sure�that�the�brakes�are�able�to�cool�down�while�the�vehicle�is�moving
and�not�to�keep�the�brakes�on�the�first�time�the�vehicle�comes�to�a�stop.�As�a�result�of�the�increased
material�transfer�from�the�brake�pads�to�the�disc�after�very�hard�driving,�a�humming�noise�can�occur
which�disappears�again�after�a�short�time.
Brake�dust
Is�an�effect�of�a�high-performance�braking�system.�The�BMW�M�models�are�high-performance
vehicles�which�are�designed�for�fast�and�dynamic�driving�and�embody�a�racing�pedigree.�The�specially
designed�brakes�make�possible�the�high�braking�performance�required�by�the�vehicle�and�in�so�doing
generate�larger�amounts�of�dust�due�to�the�greater�levels�of�friction.�The�brake�dust�tells�the�customer
that�his/her�BMW�M�vehicle�has�been�driven�in�an�appropriate�manner.�What�is�important�is�to�ensure
that�it�is�regularly�removed�by�washing�the�vehicle,�as�otherwise�it�will�eat�into�the�surface�of�the�wheel.