Bleeding Brake System

Information 

• Check brake fluid quality. Only use new DOT4 brake fluid (Hydraulan 404).
• The brake fluid change interval for DOT4 brake fluid (Hydraulan 404) is 2 years.

1. Connect brake bleeding device.

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   Brake bleeding device on brake fluid reservoir

   1. 1.1  Open the brake fluid reservoir.
   2. 1.2  Connect the bleeding device to the reservoir and switch it on.
   3. 1.3  Set the bleeding pressure to 2.0 bar (29 psi).

      Information 

      • On vehicles with a vacuum-controlled brake booster, a helper must slowly and continuously press the brake pedal during the bleeding process.

      Information 

      • To check the escaping brake fluid, ensure absolute cleanliness and make sure there are no air bubbles.
      • A transparent hose and a collecting bottle must be used to determine the amount of brake fluid used.

      Information 

      • Bleed the brake calliper at both bleeder valves.
      • Bleed the outer bleeder valve first.
2. Bleed the brake system at the brake callipers in the following sequence: rear right/rear left/front right/front left.

   See information about vehicles with vacuum-controlled brake booster (helper for pedal actuation)!

   1. 2.1 On GT3 vehicles,  have a helper actuate the brake pedal slowly and continuously during the bleeding process.
   2. 2.2  Open protection cap -1-  and open the bleeder valve -2-  outside until clear, bubble-free brake fluid emerges.

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      Protection cap and bleeder valve (shown on GT3 front axle)

   3. 2.3  Tighten the outside of the bleeder valve -2-  and close the protective cap -1-  .
      • Rear bleeder valves not  GT3 vehicles: > Tightening torque 14 Nm (10.3 ftlb.) 
      • Rear bleeder valves on GT3 vehicles: > Tightening torque 12 Nm (8.9 ftlb.) + 4 Nm (3 ftlb.) 
      • Front bleeder valves not  GT3 vehicles: > Tightening torque 14 Nm (10.3 ftlb.) +/- 2 Nm (1.5 ftlb.) 
      • Front bleeder valves on GT3 vehicles: > Tightening torque 17 Nm (12.5 ftlb.) + 3 Nm (2.2 ftlb.) 
   4. 2.4  Open protection cap -3-  and open the bleeder valve -4-  inside until clear, bubble-free brake fluid emerges.
   5. 2.5  Tighten internal bleeder valve -4-  and close protective cap -3-  .

      Tightening torques analogous to Step 2.3.

      Only when replacing the hydraulic unit: Bleed the secondary circuit.

      Information 

      • Only when replacing the hydraulic unit: Bleed the secondary circuit.

      Information 

      Press the brake pedal down fully about every 5 seconds.

      Information 

      High brake fluid loss when bleeding:

      • Make sure that there is sufficient brake fluid left (the reservoir must not run dry).
      • Empty the collecting bottle after every bleeding procedure.

      Information 

      • Bleed the brake calliper at both bleeder valves.
      • Bleed the outer bleeder valve first.
3. Ventilate the secondary circuit using the function on the PIWIS Tester. 
   1. 3.1  In Control unit overview,  select => Brake electronics (PSM with parking brake)  and press F12 to confirm.
   2. 3.2  Select Maintenance/repairs  => Service bleeding  and start the procedure.
   3. 3.3  Follow the instructions on the PIWIS Tester  and pay particular attention to the following:
      1. 3.3.1  Leave the bleeding device connected to the reservoir with a further 2.0 bar pressure.
      2. 3.3.2  Vent the brake system at both bleeder valves on the brake callipers (follow sequence shown on the PIWIS Tester  ).

         Keep pressing the brake pedal at the same time (get another person to help).

      3. 3.3.3  Open protection caps and open the bleeder valves until clear, bubble-free brake fluid emerges.
      4. 3.3.4 Tighten bleeder valves (not GT3 vehicles) -1-  and close protective caps.

         Courtesy of PORSCHE CARS NORTH AMERICA, INC.

         Brake calliper for bleeder valves review of front axle)

         Rear bleeder valves: > Tightening torque 14 Nm (10.3 ftlb.) 

         Front bleeder valves -1-  : > Tightening torque 14 Nm (10.3 ftlb.) +/- 2 Nm (1.5 ftlb.) 

      5. 3.3.5 Bleeder valves GT3 vehicles:

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         Protection cap and bleeder valve is shown on GT3 front axle)

         Brake calliper front bleeder valves -2 and 4-  : > Tightening torque 17 Nm (12.5 ftlb.) + 3 Nm (2.2 ftlb.) 

         Brake calliper rear bleeder valves: > Tightening torque 12 Nm (8.9 ftlb.) + 4 Nm (3 ftlb.) 

4. Pull off bleeder hoses.

   Information 

   The brake fluid level in the reservoir must be between the MIN and MAX markings after bleeding the brake system.

5. Unscrew bleeding device adapter from the reservoir and correct the brake fluid level if necessary.
6. Close the cap on the brake fluid reservoir.
7. Start the engine and check brake pedal travel and pedal feel.