Checking Front PCCB Brake Discs (Wear Assessment)

Information 

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Measurement markings with new friction coating technology

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Markings and values (new value/wear value)

• The validity of the measuring method using> VAS 6813 - Tester for PCCB brake discs is - recognisable by the three markings and values lasered at an offset of 120° on the brake disc hub -Arrows- . 
• > VAS 6813 - Tester for PCCB brake discs 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, replace the front brake discs. 

  > 465119 - REMOVING AND INSTALLING FRONT PCCB BRAKE DISC 

Information 

• The brake disc temperature must be in the range between 0°C and 40°C during the measurement. 
• Check tester before taking measurements and calibrate it if necessary. Follow the operating instructions provided by the equipment manufacturer. 
• Important for Quick measurement: A metallic heat shield will lower the measured value. 

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. 
• Carry out wear assessment on the brake discs and check the condition of the brake pads before and after every race track use (component temperatures are significantly higher than temperatures during "normal" driving). 

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 

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).

1. Use > VAS 6813 - Tester for PCCB brake discs  to check 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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         Position of 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 on brake disc

   2. 1.2 Exact measurement:  Wheel and brake calliper removed.
      1. 1.2.1 Remove front brake calliper.

         > 473919 - REMOVING AND INSTALLING FRONT BRAKE CALLIPER - PORTION ON "REMOVING"

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

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         Position of tester on brake disc

      3. 1.2.3 Compare the values you read off with the wear value -3-  .

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         Markings and values on brake disc

      4. 1.2.4 If the wear value -3-  is reached or if the measured value is less than the wear value at a measuring point, replace front brake discs.

         > 465119 - REMOVING AND INSTALLING FRONT BRAKE DISC (PCCB) 

         NOTIFICATION 

         Work must not be carried out on the bores in the brake disc friction surface 

         • Risk of damage to brake discs 
           1. → Clean the bores on PCCB brake discs with high-pressure cleaning equipment if necessary. Observe the relevant environmental and safety regulations.
           2. → Do not machine the bores. Drilling or counter-sinking is not permitted.
2. Visual inspection of the brake disc friction surfaces for surface changes.
   1. 2.1 Check brake disc friction surface for build-up.

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

      • Check ventilation (brake cooling): All components are fitted, secured correctly and not damaged. Carry out repairs if necessary.
      • Check brake pad quality: Use the correct brake pads if the vehicle is driven on a race track.
      • 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 1 cm² .
   3. 2.3 If specified values are exceeded, replace the affected front brake disc.

      > 465119 - REMOVING AND INSTALLING FRONT BRAKE DISC (PCCB) 

   Information 

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

     > 465119 - REMOVING AND INSTALLING FRONT BRAKE DISC (PCCB) 

3. Checking 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 > Width/depth 2 mm 
   • Max. permitted length > Length 10 mm 

     Max. 3 damaged edges permitted