Checking Rear Pccb Brake Discs (Wear Assessment)

Information 

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Measurement markings with new friction coating technology

465319 REMOVING AND INSTALLING REAR BRAKE DISC 

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Markings and values (new value/wear value)

• The validity of the measuring method using  > VAS 6813 - PCCB Brake Disc Tester is recognisable by the three markings and values lasered at an offset of 120° on the brake disc hub -Arrows-  .
• > VAS 6813 - PCCB Brake Disc Tester is used to measure the damage to the carbon fibre-reinforced material. The lower the measured value, the more carbon fibres in the internal structure of the brake disc are damaged (wear caused by the effects of temperature). 
• The markings consist of the measuring point numbers 1 to 3 -X- (figure shows measuring point number 1), the measurement marking -1- (line), the new value -2- and the wear value -3-  .
• If one of the three wear values -3- is reached or if the measured value is less than one of the three wear values, the rear brake discs must be replaced. 

Information 

• The brake disc temperature must be between  > Temperature 0°C and  > Temperature 40°C when taking measurements. 
• The tester must be checked in accordance with the operating instructions provided by the equipment manufacturer before taking measurements and must be calibrated if necessary. 
• Important for quick measurement: A metallic heat shield will lower the measured value. 

Information 

When taking measurements, the tester must be positioned over the entire surface of the brake disc with the roller stops and the underside of the device -arrows-  .

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Measuring procedure/tester (roller stops)

Information 

• The remaining service life of the brake disc can be estimated using the previously stored data and measured values recorded during service intervals/workshop visits based on the mileage. 
• The value is reduced by approx. 2 to 5 units per brake pad set (depending on the axle and brake pad) - not valid for race track use and if brake pads not approved by Porsche are used. 
• Wear assessment of the brake discs must be carried out and the condition of the brake pads must be checked before and after every race track use (component temperatures are significantly higher than temperatures during "normal" driving). 

Information 

465319 REMOVING AND INSTALLING REAR BRAKE DISC 

• If there is edge damage on the brake disc friction surfaces, only replace the affected brake disc. 

1. Use > VAS 6813 - PCCB Brake Disc Tester  to determine the wear condition.

   A differentiation is made between a quick measurement  See and an exact measurement See.

   1. 1.1 Quick measurement:  Brake calliper fitted (with or without wheel).

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      Quick measurement with wheel

      1. 1.1.1  Align laser beam -2-  with the measurement marking on the brake disc hub.

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         Positioning tester on brake disc

      2. 1.1.2  Compare the values you read off with the wear value -3-  .

         If the wear value -3-  is reached or if the measured value is less than the wear value at a measuring point, carry out an exact measurement  See.

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         Markings and values

   2. 1.2 Exact measurement:  Wheel and brake calliper removed.
      1. 1.2.1  Loosen rear brake calliper.

         474109 LOOSENING AND SECURING REAR BRAKE CALLIPER

         Information 

         Once removed, the brake calliper must not be placed closer than 50 millimetres from the back of the brake disc (see operating instructions supplied with the measuring equipment).

      2. 1.2.2  Align laser beam -2-  with the measurement marking on the brake disc hub.

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         Positioning tester on brake disc

      3. 12.3  Compare the values you read off with the wear value.

         If the wear value -3-  is reached or if the measured value is less than the wear value at a measuring point, replace rear brake discs.

         465319 REMOVING AND INSTALLING REAR BRAKE DISC 

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         Markings and values

2. Visual inspection of the brake disc friction surfaces for surface changes.
   NOTE: NOTIFICATION 
   Work must not be carried out on the bores in the brake disc friction surface 

   • Risk of damage to brake discs 

     → Clean the bores on PCCB brake discs with high-pressure cleaning equipment if necessary. Observe the relevant environmental and safety regulations.

     → Do not machine the bores. Drilling or counter-sinking is not permitted.

   1. 2.1  Check for build-up on brake disc friction surface.

      If there is a build-up on the pad, also check the following points:

      • Check ventilation (brake cooling): All components are present, secured correctly and undamaged. Carry out repairs if necessary.
      • Check brake pad quality. Use appropriate brake pads if the vehicle is driven on a racing circuit.
      • The perforation bores in the brake discs must not be blocked. Clear them if necessary.
   2. 2.2  Check brake disc for flaking/fractures as a result of unusual usage conditions (e.g. stone chip damage).

      Flaking/fractures are only permitted up to a size of > Area 1 cm ²  !

   3. 2.3  If specified values are exceeded, replace the affected rear brake disc.

      465319 REMOVING AND INSTALLING REAR BRAKE DISC 

3. Check brake discs for edge damage > Edge damage on PCCB brake disc  .

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   Edge damage on PCCB brake disc

   • Max. permitted > Width/depth 2 mm 
   • Max. permitted > Length 10 mm 
   • Max. 3 damaged edges permitted