Checking Rear Pccb Brake Discs (Wear Assessment)

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.

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 - 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, replace the rear brake discs. 

> 465419 REMOVING AND INSTALLING REAR 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 

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

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)

1. Use > VAS 6813 - Tester for PCCB brake discs  to check the wear condition.

   A differentiation is made between a quick measurement (See "1.1 Quick measurement:" below)  and an exact measurement (See "1.2 Exact measurement:" below)  .

   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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         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 "1.2 Exact measurement:" below)  .

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      Markings and values

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

         > 474119 REMOVING AND INSTALLING REAR BRAKE CALLIPER

         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)

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

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         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

      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 rear brake discs.

         > 465419 REMOVING AND INSTALLING REAR PCCB BRAKE DISC

2. Visual inspection of the brake disc friction surfaces for surface changes.
   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.

      > 465419 REMOVING AND INSTALLING REAR PCCB BRAKE DISC

   Information 

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

   > 465419 REMOVING AND INSTALLING REAR PCCB BRAKE DISC

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

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

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Edge damage on PCCB brake disc