Adjusting And Calibrating Parking-Brake Shoes

Information 

• The electric parking brake with asbestos-free brake pads must never be adjusted in such a way that the pad has to grind free during operation  . → 468350 GRINDING DOWN PARKING-BRAKE SHOES 
• Adjustments must only be carried out at the two rear wheel adjustment devices  .
• Make sure that the EPB cables are routed and guided correctly  .

In the event of unfavorable tolerances, the brake pads may prevent the brake disc from turning freely. If this happens, the brake pads must be pressed back slightly and uniformly using water pump pliers.

1. Raise the vehicle. → 4X00IN LIFTING THE VEHICLE
2. Remove rear wheels. → 440519 REMOVING AND INSTALLING WHEEL
3. Release the EPB so that the brake discs can turn freely.
4. Move the brake shoes into installation position using the Porsche System Tester. Select >>Parking brake<< in the control unit overview. Select >>Drive links/checks>>All<< >>Move to installation position<<.
5. Adjust brake shoes on both sides. To do this, turn the relevant brake disc with the opening to the adjustment device position. Using a screwdriver, adjust the adjustment device until the brake disc can no longer be turned. The subsequent torque of the brake disc must be greater than 100 Nm (74 ft. lb.). Then loosen 17 (+/- 1) clicks of the adjustment device (brake discs must be able to turn freely).
6. Using the Porsche System Tester, select >>Parking brake<< in the control unit overview. Select >>Maintenance/repairs<< >>Check parking brake basic setting<<.

   It may be necessary to fine-tune the adjustment device after selecting >>Check parking brake basic setting<<.

   Location	Description	Type	Basic value	Tolerance 1	Tolerance 2
   Actual dimension	Displayed on the Tester! Actual gap dimension at left and right measured between the shoe and drum in millimetres.	Control value	000 mm
   Required dimension	Displayed on the Tester! Required dimension between the shoe and drum in millimetres.	Control value	+2.2 mm	+/-0.3 mm
   Adjustment dimension	Must be calculated! Value (in millimetres) by which the adjustment device must be turned.	Control value	000 mm

   Adjustment dimension = required dimension - actual dimension  (required dimension minus actual dimension)

   Fig 1: Calibrating Parking-Brake Shoes

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.
   Fig 2: Adjusting Parking-Brake Shoes

   Courtesy of PORSCHE CARS NORTH AMERICA, INC.

   → Control value: 0.15 mm 

   Corresponds to 1 click on the adjustment device 

   Information 

   A calculated value in the positive range means: Turn adjustment device towards A - loosen.

   A calculated value in the negative range means: Turn adjustment device towards B - tighten.

   Adjustment dimension = required dimension - actual dimension (required dimension minus actual dimension) 

   Example:

   Actual dimension: 2.6 mm

   Required dimension: 2.0 mm (+/- 0.3 mm)

   Adjustment dimension = required dimension - actual dimension

   Adjustment dimension = 2.0 mm - 2.6 mm

   Adjustment dimension = -0.6 mm

   -0.6 mm: 0.15 mm = - 4 clicks (0.15 mm corresponds to one click!)

   Adjustment dimension = -0.6 mm: This means that the gap dimension is too big and the adjustment device must be adjusted towards B - tighten.

7. Grind parking-brake shoes (not PCCB!) → 468350 REWORKING (GRINDING) PARKING-BRAKE SHOES .
8. Calibrate the EPB using the Porsche System Tester. To do this, select >>Parking brake<< in the control unit overview. Select >>Maintenance/repairs<< >>Calibration<<.
9. To check the function of the EPB, actuate the EPB button several times (press 2-3 times) and make sure that the actuators open and close on both sides.

   Position disc brake pads by operating the brake several times.

10. Fit wheels → INSTALLING WHEEL - section on "Installing".