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Removing And Installing Brake Booster: Removal

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NOTE:
  • The brake master cylinder -B-  and the hydraulic unit -D-  must be removed to remove and install the brake booster -C-  .
    Fig 1: Locating Brake Booster, Hydraulic Unit And Master Cylinder
    G03103434Courtesy of PORSCHE OF NORTH AMERICA, INC.
  • The assembly of the brake master cylinder -B-  with the brake booster -C-  must not be disconnected for removal and installation if both parts should continue to be used!
  1. Switch off ignition. Remove covers -A and B-  .
    Fig 2: Removing Covers
    G03103435Courtesy of PORSCHE OF NORTH AMERICA, INC.
  2. Remove spare wheel.
  3. Drain brake fluid expansion tank. To do so, suck brake fluid out of the expansion tank or pump out the brake fluid using the brake pedal via a front and a rear brake caliper (use collecting bottle).
  4. For vehicles with manual transmission, remove the clutch line at the reservoir.
    • Press on the ring to do this (unlocking) and pull the line out of the reservoir at the same time.
  5. Disconnect the electrical line (plug) on the reservoir.
  6. Undo the brake lines on the brake master cylinder. Close the brake lines and the brake line connections with suitable plugs. Undo the fastening nuts -A-  of the brake master cylinder. See Fig 3 . Pull out brake master cylinder.
    Fig 3: Locating Master Cylinder Fastening Nuts
    G03103436Courtesy of PORSCHE OF NORTH AMERICA, INC.
    • The brake master cylinder must be disconnected from the brake booster if both parts should continue to be used!
    NOTE:
    • In the case of assembly work on the hydraulic connections, the electrical plug connections on the hydraulic unit must always be connected!
    • This prevents the plug connections on the hydraulic unit or in the plugs inside from being splashed with brake fluid or water!
    • Any damp plug must be wiped dry before being disconnected from the plug on the hydraulic unit!
    • Brake fluid on electrical contacts (even thinned brake fluid) leads to corrosion and may cause faults in the system!
  7. Remove hydraulic unit. To remove the hydraulic unit, carry out the following removal procedure:
    • Undo the brake lines on the hydraulic unit.
    • Close the brake lines and the brake line connections with suitable plugs.
    • Pull the plug off the pressure sensor if present (vehicles with PSM 5.7).
    • Unlock/disconnect the control module connector on the hydraulic unit. Cover the plug connection and the plug!
    • Undo and guide out the hydraulic unit.
  8. Remove holder of hydraulic unit (if still installed).
  9. Separate the 2 push rods from each other (loosen). For this purpose, remove the fastening nut (fastening nut, standard as of April 2001)-arrow-  . See Fig 4 . To make the retainer or fastening nut accessible, adjust the bellows positioned above or undo on the body (according to bellow variant).
    Fig 4: Removing Fastening Nut
    G03103437Courtesy of PORSCHE OF NORTH AMERICA, INC.
  10. Disengage the vacuum line on the brake booster. Undo the fastening screws -arrows-  of the brake booster (Torx T 45). See Fig 4 . Pull out brake booster.
Fig 5: Locating Brake Booster Fastening Screws
G03103438Courtesy of PORSCHE OF NORTH AMERICA, INC.


  1. Switch off ignition. Remove cover -A + B-  and battery cover. See Fig 1 .
    Fig 1: Removing Cover And Battery Cover
    G03103456Courtesy of PORSCHE OF NORTH AMERICA, INC.
  2. Remove spare wheel.
  3. Remove brake booster -C-  . See Fig 2 and REMOVING AND INSTALLING BRAKE BOOSTER  .
    Fig 2: Identifying Brake Booster Assembly
    G03103457Courtesy of PORSCHE OF NORTH AMERICA, INC.
    NOTE:
    • The brake master cylinder -B-  and the hydraulic unit -D-  must be removed to remove and install the brake booster -C-  . See Fig 2 .
    • The assembly of the brake master cylinder -B-  with the brake booster -C-  must not be disconnected for removal and installation if both parts should be continued to be used. See Fig 2 .
  4. Remove battery -1-  (necessary to remove intermediate piece -11-  ). Remove alarm horn on the intermediate piece -11-.  . See Fig 3 .
    Fig 3: Removing Battery And Alarm Horn
    G03103458Courtesy of PORSCHE OF NORTH AMERICA, INC.
  5. Undo intermediate piece -11- arrow-  (2 M8 nuts and hexagon socket head bolt) and remove in the direction of the battery. Unclip air-conditioning line -2-  from the holder. See Fig 3 .
  6. Remove the bellows -1-  on the fire wall and the bellows -2-  on the brake booster. Pull off the grommet (rubber groove ring) -3-  . See Fig 4 .
    Fig 4: Removing Bellows On Fire Wall And Bellows On Brake Booster
    G03103459Courtesy of PORSCHE OF NORTH AMERICA, INC.
    NOTE:
    • The grommet -3-  is not replaced. See Fig 4 .
  7. Undo brake pushrod -9-  on the brake pedal and remove. See Fig 5 .
Fig 5: Identifying Brake Pushrod
G03103460Courtesy of PORSCHE OF NORTH AMERICA, INC.
NOTE:
  • The former brake pushrod -9-  with guide (double rib) -arrow-  is to be replaced with the brake pushrod -9.1-  without guide! See Fig 5 .
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