Removing and installing brake booster: Removal

NOTE:

• To remove and install brake booster -C-, the brake master cylinder -B-, the hydraulic unit -D- and the booster pump -A- in vehicles with PSM (GT2 without PSM) must be removed. Refer to Fig 1 .
• 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!

Fig 1: Identifying Brake Booster, Brake Master Cylinder, Hydraulic Unit And Booster Pump

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1. Switch off ignition. Remove cover -A and B-  .
   Fig 2: Removing Covers

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2. 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).
3. Disconnect the electrical line (plug) on the reservoir.
4. 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. Pull out brake master cylinder.
   • The brake master cylinder must be disconnected from the brake booster if both parts should continue to be used!
   • -A-  = Brake master cylinder fastening nuts (Fig 3 )
   • -B-  = Brake booster fastening screws (Torx)
   Fig 3: Identifying Brake Master Cylinder Fastening Nuts And Brake Booster Fastening Screws (Torx)
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5. In vehicles with PSM, remove the booster pump -1-  with the holder-1a-  . Refer to Fig 4 . For the removal of the booster pump, carry out the following removal steps:
   • Remove suction line -2-  for booster pump. Refer to Fig 4 . Undo pressure pipe on the booster pump -3-  . Close the lines and the pump connections with suitable plugs.
   • Release plug -4- -arrows-  and disconnect. Remove connector housing rearwards from out of the holder -moving arrow-  . Refer to Fig 4 .
   • Undo the three plastic fastening nuts -5-  and remove the booster pump -1-  with the holder -1a-  . Refer to Fig 4 .
   Fig 4: Identifying Brake Booster Components
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   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!
6. 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.
7. Remove holder of hydraulic unit (if still installed).
8. Separate the 2 push rods from each other (loosen). For this purpose, remove the fastening nut (fastening nut, standard as of April 2001)-arrow-  . To make the retainer or the fastening nut accessible, adjust the bellows positioned above the body.
   Fig 5: Locating Push Rod Fastening Nut

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9. Disengage the vacuum line on the brake booster. Undo the fastening screws -arrows-  of the brake booster (Torx T 45). Pull out brake booster.
   Fig 6: Removing Fastening Screws Of Brake Booster

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