911 Turbo AWD F6-3600cc 3.6L SOHC Twin Turbo (1997)
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After the pump unit has switched off, check brake fluid level. Never top up beyond the "Max. mark".
Re- 2: Bleeding the ABD Circuit
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Preparation: Bleed brakes in conventional manner (for master cylinder circuits, refer to Re- 1).
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The bleeder device remains connected (switched on) when the ABD circuit is bled. In addition, the booster circuit must be depressurized.
Bleeding pressure: approx. 1.5 to 2.0 bar. Overflow hose (vent) is blocked with hose clamp at brake fluid reservoir.
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Connect System Tester 9288 to diagnostic socket. Switch on ignition. Select "Bleed" menu.
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Open rear right bleeder valve (use recipient bottle).
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Press Start button on System Tester. This causes specific functions in the hydraulic unit to be started (return pump, switchoff valve and
switchover valve are triggered).
Bleed until bubble-free brake fluid escapes. Also depress brake pedal (pump at pedal) across the entire pedal travel (to the stop) during the
entire bleeding process (at least 10 times).
Caution: Double the pumping cycles on high-mileage vehicles or older vehicles but use only half the brake master cylinder stroke in these cases
(to avoid damage to the master cylinder, i.e. primary cups).
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Close rear right bleeder valve. Then press Stop button immediately on System Tester.
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Switch off ignition and disconnect System Tester.
Switch off and disconnect bleeder device. Remove hose clamp from overflow hose (vent).
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Fill pressure accumulator completely by reconnecting the electrical connector.
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Correct brake fluid level after the pump unit has switched off. Never top up beyond the "Max. mark".
Re- 3: Bleeding the Brake Booster Circuit
Notes
The bleeding process includes two steps. The first step may be omitted in certain cases.
1st step: Preparatory operations for initial fitting or refitting.
2nd step: Bleeding the pressure accumulator.
After replacing or removing the pump unit and pressure accumulator, follow these instructions carefully. If a different process is selected, the
brake fluid may foam excessively.
Depressurize booster circuit before working on this circuit (e.g. to remove or fit components).
To depressurize, pull off electrical connector from pressurizing pump (pump unit) (refer to illustration) and actuate brake pedal approx. 25
times. The system is depressurized as soon as the brake pedal feels hard when it is actuated.
To pull off and reconnect the electrical connector on the pressurizing pump, press on center of the connector locking clamp.
Preparatory operations for initial fitting or refitting: 1st step
This operation is only required if the pump unit and pressure accumulator have been replaced or refitted and if the suction line has been
opened or if the reservoir was empty prior to the bleeding process.
In all other cases, start with the 2nd step
